--- _id: '52723' abstract: - lang: eng text: Miller's rule is an empirical relation between the nonlinear and linear optical coefficients that applies to a large class of materials but has only been rigorously derived for the classical Lorentz model with a weak anharmonic perturbation. In this work, we extend the proof and present a detailed derivation of Miller's rule for an equivalent quantum-mechanical anharmonic oscillator. For this purpose, the classical concept of velocity-dependent damping inherent to the Lorentz model is replaced by an adiabatic switch-on of the external electric field, which allows a unified treatment of the classical and quantum-mechanical systems using identical potentials and fields. Although the dynamics of the resulting charge oscillations, and hence the induced polarizations, deviate due to the finite zero-point motion in the quantum-mechanical framework, we find that Miller's rule is nevertheless identical in both cases up to terms of first order in the anharmonicity. With a view to practical applications, especially in the context of ab initio calculations for the optical response where adiabatically switched-on fields are widely assumed, we demonstrate that a correct treatment of finite broadening parameters is essential to avoid spurious errors that may falsely suggest a violation of Miller's rule, and we illustrate this point by means of a numerical example. article_type: original author: - first_name: Maximilian Tim full_name: Meyer, Maximilian Tim last_name: Meyer - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Meyer MT, Schindlmayr A. Derivation of Miller’s rule for the nonlinear optical susceptibility of a quantum anharmonic oscillator. Journal of Physics B: Atomic, Molecular and Optical Physics. doi:10.1088/1361-6455/ad369c' apa: 'Meyer, M. T., & Schindlmayr, A. (n.d.). Derivation of Miller’s rule for the nonlinear optical susceptibility of a quantum anharmonic oscillator. Journal of Physics B: Atomic, Molecular and Optical Physics. https://doi.org/10.1088/1361-6455/ad369c' bibtex: '@article{Meyer_Schindlmayr, title={Derivation of Miller’s rule for the nonlinear optical susceptibility of a quantum anharmonic oscillator}, DOI={10.1088/1361-6455/ad369c}, journal={Journal of Physics B: Atomic, Molecular and Optical Physics}, publisher={IOP Publishing}, author={Meyer, Maximilian Tim and Schindlmayr, Arno} }' chicago: 'Meyer, Maximilian Tim, and Arno Schindlmayr. “Derivation of Miller’s Rule for the Nonlinear Optical Susceptibility of a Quantum Anharmonic Oscillator.” Journal of Physics B: Atomic, Molecular and Optical Physics, n.d. https://doi.org/10.1088/1361-6455/ad369c.' ieee: 'M. T. Meyer and A. Schindlmayr, “Derivation of Miller’s rule for the nonlinear optical susceptibility of a quantum anharmonic oscillator,” Journal of Physics B: Atomic, Molecular and Optical Physics, doi: 10.1088/1361-6455/ad369c.' mla: 'Meyer, Maximilian Tim, and Arno Schindlmayr. “Derivation of Miller’s Rule for the Nonlinear Optical Susceptibility of a Quantum Anharmonic Oscillator.” Journal of Physics B: Atomic, Molecular and Optical Physics, IOP Publishing, doi:10.1088/1361-6455/ad369c.' short: 'M.T. Meyer, A. Schindlmayr, Journal of Physics B: Atomic, Molecular and Optical Physics (n.d.).' date_created: 2024-03-22T08:44:39Z date_updated: 2024-03-22T08:47:41Z department: - _id: '296' - _id: '230' - _id: '15' - _id: '170' - _id: '35' doi: 10.1088/1361-6455/ad369c language: - iso: eng publication: 'Journal of Physics B: Atomic, Molecular and Optical Physics' publication_identifier: eissn: - 1361-6455 issn: - 0953-4075 publication_status: accepted publisher: IOP Publishing quality_controlled: '1' status: public title: Derivation of Miller's rule for the nonlinear optical susceptibility of a quantum anharmonic oscillator type: journal_article user_id: '458' year: '2024' ... --- _id: '30288' abstract: - lang: eng text: Lithium niobate (LiNbO3), a material frequently used in optical applications, hosts different kinds of polarons that significantly affect many of its physical properties. In this study, a variety of electron polarons, namely free, bound, and bipolarons, are analyzed using first-principles calculations. We perform a full structural optimization based on density-functional theory for selected intrinsic defects with special attention to the role of symmetry-breaking distortions that lower the total energy. The cations hosting the various polarons relax to a different degree, with a larger relaxation corresponding to a larger gap between the defect level and the conduction-band edge. The projected density of states reveals that the polaron states are formerly empty Nb 4d states lowered into the band gap. Optical absorption spectra are derived within the independent-particle approximation, corrected by the GW approximation that yields a wider band gap and by including excitonic effects within the Bethe-Salpeter equation. Comparing the calculated spectra with the density of states, we find that the defect peak observed in the optical absorption stems from transitions between the defect level and a continuum of empty Nb 4d states. Signatures of polarons are further analyzed in the reflectivity and other experimentally measurable optical coefficients. author: - first_name: Falko full_name: Schmidt, Falko id: '35251' last_name: Schmidt orcid: 0000-0002-5071-5528 - first_name: Agnieszka L. full_name: Kozub, Agnieszka L. id: '77566' last_name: Kozub orcid: https://orcid.org/0000-0001-6584-0201 - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann orcid: 0000-0002-4476-223X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Schmidt F, Kozub AL, Gerstmann U, Schmidt WG, Schindlmayr A. Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response. In: Corradi G, Kovács L, eds. New Trends in Lithium Niobate: From Bulk to Nanocrystals. MDPI; 2022:231-248. doi:10.3390/books978-3-0365-3339-1' apa: 'Schmidt, F., Kozub, A. L., Gerstmann, U., Schmidt, W. G., & Schindlmayr, A. (2022). Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response. In G. Corradi & L. Kovács (Eds.), New Trends in Lithium Niobate: From Bulk to Nanocrystals (pp. 231–248). MDPI. https://doi.org/10.3390/books978-3-0365-3339-1' bibtex: '@inbook{Schmidt_Kozub_Gerstmann_Schmidt_Schindlmayr_2022, place={Basel}, title={Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response}, DOI={10.3390/books978-3-0365-3339-1}, booktitle={New Trends in Lithium Niobate: From Bulk to Nanocrystals}, publisher={MDPI}, author={Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}, editor={Corradi, Gábor and Kovács, László}, year={2022}, pages={231–248} }' chicago: 'Schmidt, Falko, Agnieszka L. Kozub, Uwe Gerstmann, Wolf Gero Schmidt, and Arno Schindlmayr. “Electron Polarons in Lithium Niobate: Charge Localization, Lattice Deformation, and Optical Response.” In New Trends in Lithium Niobate: From Bulk to Nanocrystals, edited by Gábor Corradi and László Kovács, 231–48. Basel: MDPI, 2022. https://doi.org/10.3390/books978-3-0365-3339-1.' ieee: 'F. Schmidt, A. L. Kozub, U. Gerstmann, W. G. Schmidt, and A. Schindlmayr, “Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response,” in New Trends in Lithium Niobate: From Bulk to Nanocrystals, G. Corradi and L. Kovács, Eds. Basel: MDPI, 2022, pp. 231–248.' mla: 'Schmidt, Falko, et al. “Electron Polarons in Lithium Niobate: Charge Localization, Lattice Deformation, and Optical Response.” New Trends in Lithium Niobate: From Bulk to Nanocrystals, edited by Gábor Corradi and László Kovács, MDPI, 2022, pp. 231–48, doi:10.3390/books978-3-0365-3339-1.' short: 'F. Schmidt, A.L. Kozub, U. Gerstmann, W.G. Schmidt, A. Schindlmayr, in: G. Corradi, L. Kovács (Eds.), New Trends in Lithium Niobate: From Bulk to Nanocrystals, MDPI, Basel, 2022, pp. 231–248.' date_created: 2022-03-13T15:28:47Z date_updated: 2023-04-20T15:58:51Z ddc: - '530' department: - _id: '296' - _id: '230' - _id: '429' - _id: '295' - _id: '15' - _id: '170' - _id: '35' - _id: '790' doi: 10.3390/books978-3-0365-3339-1 editor: - first_name: Gábor full_name: Corradi, Gábor last_name: Corradi - first_name: László full_name: Kovács, László last_name: Kovács language: - iso: eng page: 231-248 place: Basel project: - _id: '53' name: 'TRR 142: TRR 142' - _id: '55' name: 'TRR 142 - B: TRR 142 - Project Area B' - _id: '69' name: 'TRR 142 - B4: TRR 142 - Subproject B4' - _id: '54' name: 'TRR 142 - A: TRR 142 - Project Area A' - _id: '166' name: 'TRR 142 - A11: TRR 142 - Subproject A11' - _id: '168' name: 'TRR 142 - B07: TRR 142 - Subproject B07' - _id: '52' name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing' publication: 'New Trends in Lithium Niobate: From Bulk to Nanocrystals' publication_identifier: eisbn: - 978-3-0365-3339-1 isbn: - 978-3-0365-3340-7 publication_status: published publisher: MDPI quality_controlled: '1' status: public title: 'Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response' type: book_chapter user_id: '16199' year: '2022' ... --- _id: '26627' abstract: - lang: eng text: Many-body perturbation theory based on density-functional theory calculations is used to determine the quasiparticle band structures and the dielectric functions of the isomorphic ferroelectrics rubidium titanyl phosphate (RbTiOPO4) and potassium titanyl arsenide (KTiOAsO4). Self-energy corrections of more than 2 eV are found to widen the transport band gaps of both materials considerably to 5.3 and 5.2 eV, respectively. At the same time, both materials are characterized by strong exciton binding energies of 1.4 and 1.5 eV, respectively. The solution of the Bethe-Salpeter equation based on the quasiparticle energies results in onsets of the optical absorption within the range of the measured data. article_number: '015002' article_type: original author: - first_name: Sergej full_name: Neufeld, Sergej id: '23261' last_name: Neufeld - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 citation: ama: 'Neufeld S, Schindlmayr A, Schmidt WG. Quasiparticle energies and optical response of RbTiOPO4 and KTiOAsO4. Journal of Physics: Materials. 2022;5(1). doi:10.1088/2515-7639/ac3384' apa: 'Neufeld, S., Schindlmayr, A., & Schmidt, W. G. (2022). Quasiparticle energies and optical response of RbTiOPO4 and KTiOAsO4. Journal of Physics: Materials, 5(1), Article 015002. https://doi.org/10.1088/2515-7639/ac3384' bibtex: '@article{Neufeld_Schindlmayr_Schmidt_2022, title={Quasiparticle energies and optical response of RbTiOPO4 and KTiOAsO4}, volume={5}, DOI={10.1088/2515-7639/ac3384}, number={1015002}, journal={Journal of Physics: Materials}, publisher={IOP Publishing}, author={Neufeld, Sergej and Schindlmayr, Arno and Schmidt, Wolf Gero}, year={2022} }' chicago: 'Neufeld, Sergej, Arno Schindlmayr, and Wolf Gero Schmidt. “Quasiparticle Energies and Optical Response of RbTiOPO4 and KTiOAsO4.” Journal of Physics: Materials 5, no. 1 (2022). https://doi.org/10.1088/2515-7639/ac3384.' ieee: 'S. Neufeld, A. Schindlmayr, and W. G. Schmidt, “Quasiparticle energies and optical response of RbTiOPO4 and KTiOAsO4,” Journal of Physics: Materials, vol. 5, no. 1, Art. no. 015002, 2022, doi: 10.1088/2515-7639/ac3384.' mla: 'Neufeld, Sergej, et al. “Quasiparticle Energies and Optical Response of RbTiOPO4 and KTiOAsO4.” Journal of Physics: Materials, vol. 5, no. 1, 015002, IOP Publishing, 2022, doi:10.1088/2515-7639/ac3384.' short: 'S. Neufeld, A. Schindlmayr, W.G. Schmidt, Journal of Physics: Materials 5 (2022).' date_created: 2021-10-20T13:00:04Z date_updated: 2023-04-20T14:01:16Z ddc: - '530' department: - _id: '296' - _id: '295' - _id: '230' - _id: '429' - _id: '15' - _id: '170' - _id: '35' doi: 10.1088/2515-7639/ac3384 external_id: isi: - '000721060500001' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2021-11-22T17:57:00Z date_updated: 2021-11-22T17:57:00Z description: Creative Commons Attribution 4.0 International Public License (CC BY 4.0) file_id: '27705' file_name: Neufeld_2022_J._Phys._Mater._5_015002.pdf file_size: 2687065 relation: main_file title: Quasiparticle energies and optical response of RbTiOPO4 and KTiOAsO4 file_date_updated: 2021-11-22T17:57:00Z funded_apc: '1' has_accepted_license: '1' intvolume: ' 5' isi: '1' issue: '1' language: - iso: eng oa: '1' project: - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '52' name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing' - _id: '168' name: 'TRR 142 - B07: TRR 142 - Subproject B07' publication: 'Journal of Physics: Materials' publication_identifier: eissn: - 2515-7639 publication_status: published publisher: IOP Publishing quality_controlled: '1' status: public title: Quasiparticle energies and optical response of RbTiOPO4 and KTiOAsO4 type: journal_article user_id: '16199' volume: 5 year: '2022' ... --- _id: '29808' abstract: - lang: ger text: Dieses Format eignet sich, um zu prüfen, inwieweit Studierende Computersimulationen und eigene kleine Programme zur Lösung typischer Probleme ihres Fachs nutzen können. Wie bei Klausuren erfolgt die Bearbeitung in begrenzter Zeit und unter Aufsicht, wird aber am Computer durchgeführt und beinhaltet neben der Programmierung auch vor- und nachbereitende Aufgaben im Kontext der fachlichen Anwendung. author: - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Schindlmayr A. Programmierung und Computersimulationen. In: Gerick J, Sommer A, Zimmermann G, eds. Kompetent Prüfungen gestalten: 60 Prüfungsformate für die Hochschullehre. 2nd ed. Waxmann; 2022:270-274. doi:10.36198/9783838558592' apa: 'Schindlmayr, A. (2022). Programmierung und Computersimulationen. In J. Gerick, A. Sommer, & G. Zimmermann (Eds.), Kompetent Prüfungen gestalten: 60 Prüfungsformate für die Hochschullehre (2nd ed., pp. 270–274). Waxmann. https://doi.org/10.36198/9783838558592' bibtex: '@inbook{Schindlmayr_2022, place={Münster}, edition={2}, title={Programmierung und Computersimulationen}, DOI={10.36198/9783838558592}, booktitle={Kompetent Prüfungen gestalten: 60 Prüfungsformate für die Hochschullehre}, publisher={Waxmann}, author={Schindlmayr, Arno}, editor={Gerick, Julia and Sommer, Angela and Zimmermann, Germo}, year={2022}, pages={270–274} }' chicago: 'Schindlmayr, Arno. “Programmierung und Computersimulationen.” In Kompetent Prüfungen gestalten: 60 Prüfungsformate für die Hochschullehre, edited by Julia Gerick, Angela Sommer, and Germo Zimmermann, 2nd ed., 270–74. Münster: Waxmann, 2022. https://doi.org/10.36198/9783838558592.' ieee: 'A. Schindlmayr, “Programmierung und Computersimulationen,” in Kompetent Prüfungen gestalten: 60 Prüfungsformate für die Hochschullehre, 2nd ed., J. Gerick, A. Sommer, and G. Zimmermann, Eds. Münster: Waxmann, 2022, pp. 270–274.' mla: 'Schindlmayr, Arno. “Programmierung und Computersimulationen.” Kompetent Prüfungen gestalten: 60 Prüfungsformate für die Hochschullehre, edited by Julia Gerick et al., 2nd ed., Waxmann, 2022, pp. 270–74, doi:10.36198/9783838558592.' short: 'A. Schindlmayr, in: J. Gerick, A. Sommer, G. Zimmermann (Eds.), Kompetent Prüfungen gestalten: 60 Prüfungsformate für die Hochschullehre, 2nd ed., Waxmann, Münster, 2022, pp. 270–274.' date_created: 2022-02-11T11:13:37Z date_updated: 2023-04-20T14:55:58Z department: - _id: '296' - _id: '170' - _id: '15' - _id: '35' doi: 10.36198/9783838558592 edition: '2' editor: - first_name: Julia full_name: Gerick, Julia last_name: Gerick - first_name: Angela full_name: Sommer, Angela last_name: Sommer - first_name: Germo full_name: Zimmermann, Germo last_name: Zimmermann language: - iso: ger page: 270-274 place: Münster publication: 'Kompetent Prüfungen gestalten: 60 Prüfungsformate für die Hochschullehre' publication_identifier: eisbn: - '9783838558592' isbn: - '9783825258597' publication_status: published publisher: Waxmann quality_controlled: '1' status: public title: Programmierung und Computersimulationen type: book_chapter user_id: '16199' year: '2022' ... --- _id: '44088' abstract: - lang: eng text: 'Hole polarons and defect-bound exciton polarons in lithium niobate are investigated by means of density-functional theory, where the localization of the holes is achieved by applying the +U approach to the oxygen 2p orbitals. We find three principal configurations of hole polarons: (i) self-trapped holes localized at displaced regular oxygen atoms and (ii) two other configurations bound to a lithium vacancy either at a threefold coordinated oxygen atom above or at a two-fold coordinated oxygen atom below the defect. The latter is the most stable and is in excellent quantitative agreement with measured g factors from electron paramagnetic resonance. Due to the absence of mid-gap states, none of these hole polarons can explain the broad optical absorption centered between 2.5 and 2.8 eV that is observed in transient absorption spectroscopy, but such states appear if a free electron polaron is trapped at the same lithium vacancy as the bound hole polaron, resulting in an exciton polaron. The dielectric function calculated by solving the Bethe–Salpeter equation indeed yields an optical peak at 2.6 eV in agreement with the two-photon experiments. The coexistence of hole and exciton polarons, which are simultaneously created in optical excitations, thus satisfactorily explains the reported experimental data.' article_number: '1586' article_type: original author: - first_name: Falko full_name: Schmidt, Falko id: '35251' last_name: Schmidt orcid: 0000-0002-5071-5528 - first_name: Agnieszka L. full_name: Kozub, Agnieszka L. id: '77566' last_name: Kozub orcid: 0000-0001-6584-0201 - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann orcid: 0000-0002-4476-223X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Schmidt F, Kozub AL, Gerstmann U, Schmidt WG, Schindlmayr A. A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate. Crystals. 2022;12(11). doi:10.3390/cryst12111586 apa: Schmidt, F., Kozub, A. L., Gerstmann, U., Schmidt, W. G., & Schindlmayr, A. (2022). A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate. Crystals, 12(11), Article 1586. https://doi.org/10.3390/cryst12111586 bibtex: '@article{Schmidt_Kozub_Gerstmann_Schmidt_Schindlmayr_2022, title={A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate}, volume={12}, DOI={10.3390/cryst12111586}, number={111586}, journal={Crystals}, publisher={MDPI AG}, author={Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}, year={2022} }' chicago: Schmidt, Falko, Agnieszka L. Kozub, Uwe Gerstmann, Wolf Gero Schmidt, and Arno Schindlmayr. “A Density-Functional Theory Study of Hole and Defect-Bound Exciton Polarons in Lithium Niobate.” Crystals 12, no. 11 (2022). https://doi.org/10.3390/cryst12111586. ieee: 'F. Schmidt, A. L. Kozub, U. Gerstmann, W. G. Schmidt, and A. Schindlmayr, “A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate,” Crystals, vol. 12, no. 11, Art. no. 1586, 2022, doi: 10.3390/cryst12111586.' mla: Schmidt, Falko, et al. “A Density-Functional Theory Study of Hole and Defect-Bound Exciton Polarons in Lithium Niobate.” Crystals, vol. 12, no. 11, 1586, MDPI AG, 2022, doi:10.3390/cryst12111586. short: F. Schmidt, A.L. Kozub, U. Gerstmann, W.G. Schmidt, A. Schindlmayr, Crystals 12 (2022). date_created: 2023-04-20T13:52:44Z date_updated: 2024-03-22T08:47:08Z ddc: - '530' department: - _id: '15' - _id: '296' - _id: '170' - _id: '295' - _id: '35' - _id: '230' - _id: '429' doi: 10.3390/cryst12111586 external_id: isi: - '000895837200001' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2023-06-11T23:59:27Z date_updated: 2023-06-12T00:22:51Z description: Creative Commons Attribution 4.0 International Public License (CC BY 4.0) file_id: '45570' file_name: crystals-12-01586-v2.pdf file_size: 1762554 relation: main_file title: A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate file_date_updated: 2023-06-12T00:22:51Z has_accepted_license: '1' intvolume: ' 12' isi: '1' issue: '11' language: - iso: eng oa: '1' project: - _id: '53' grant_number: '231447078' name: 'TRR 142: TRR 142' - _id: '54' name: 'TRR 142 - A: TRR 142 - Project Area A' - _id: '55' name: 'TRR 142 - B: TRR 142 - Project Area B' - _id: '69' grant_number: '231447078' name: 'TRR 142 - B04: TRR 142 - Subproject B04' - _id: '168' grant_number: '231447078' name: 'TRR 142 - B07: TRR 142 - Subproject B07' - _id: '166' name: 'TRR 142 - A11: TRR 142 - Subproject A11' - _id: '52' name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing' publication: Crystals publication_identifier: eissn: - 2073-4352 publication_status: published publisher: MDPI AG quality_controlled: '1' status: public title: A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate type: journal_article user_id: '458' volume: 12 year: '2022' ... --- _id: '21946' abstract: - lang: eng text: Lithium niobate (LiNbO3), a material frequently used in optical applications, hosts different kinds of polarons that significantly affect many of its physical properties. In this study, a variety of electron polarons, namely free, bound, and bipolarons, are analyzed using first-principles calculations. We perform a full structural optimization based on density-functional theory for selected intrinsic defects with special attention to the role of symmetry-breaking distortions that lower the total energy. The cations hosting the various polarons relax to a different degree, with a larger relaxation corresponding to a larger gap between the defect level and the conduction-band edge. The projected density of states reveals that the polaron states are formerly empty Nb 4d states lowered into the band gap. Optical absorption spectra are derived within the independent-particle approximation, corrected by the GW approximation that yields a wider band gap and by including excitonic effects within the Bethe-Salpeter equation. Comparing the calculated spectra with the density of states, we find that the defect peak observed in the optical absorption stems from transitions between the defect level and a continuum of empty Nb 4d states. Signatures of polarons are further analyzed in the reflectivity and other experimentally measurable optical coefficients. article_type: original author: - first_name: Falko full_name: Schmidt, Falko id: '35251' last_name: Schmidt orcid: 0000-0002-5071-5528 - first_name: Agnieszka L. full_name: Kozub, Agnieszka L. id: '77566' last_name: Kozub orcid: https://orcid.org/0000-0001-6584-0201 - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann orcid: 0000-0002-4476-223X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Schmidt F, Kozub AL, Gerstmann U, Schmidt WG, Schindlmayr A. Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response. Crystals. 2021;11:542. doi:10.3390/cryst11050542' apa: 'Schmidt, F., Kozub, A. L., Gerstmann, U., Schmidt, W. G., & Schindlmayr, A. (2021). Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response. Crystals, 11, 542. https://doi.org/10.3390/cryst11050542' bibtex: '@article{Schmidt_Kozub_Gerstmann_Schmidt_Schindlmayr_2021, title={Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response}, volume={11}, DOI={10.3390/cryst11050542}, journal={Crystals}, publisher={MDPI}, author={Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}, year={2021}, pages={542} }' chicago: 'Schmidt, Falko, Agnieszka L. Kozub, Uwe Gerstmann, Wolf Gero Schmidt, and Arno Schindlmayr. “Electron Polarons in Lithium Niobate: Charge Localization, Lattice Deformation, and Optical Response.” Crystals 11 (2021): 542. https://doi.org/10.3390/cryst11050542.' ieee: 'F. Schmidt, A. L. Kozub, U. Gerstmann, W. G. Schmidt, and A. Schindlmayr, “Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response,” Crystals, vol. 11, p. 542, 2021, doi: 10.3390/cryst11050542.' mla: 'Schmidt, Falko, et al. “Electron Polarons in Lithium Niobate: Charge Localization, Lattice Deformation, and Optical Response.” Crystals, vol. 11, MDPI, 2021, p. 542, doi:10.3390/cryst11050542.' short: F. Schmidt, A.L. Kozub, U. Gerstmann, W.G. Schmidt, A. Schindlmayr, Crystals 11 (2021) 542. date_created: 2021-05-03T09:36:13Z date_updated: 2023-04-21T11:20:15Z ddc: - '530' department: - _id: '296' - _id: '230' - _id: '429' - _id: '295' - _id: '15' - _id: '170' - _id: '35' - _id: '790' doi: 10.3390/cryst11050542 external_id: isi: - '000653822700001' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2021-05-13T16:47:11Z date_updated: 2021-05-13T16:51:41Z description: Creative Commons Attribution 4.0 International Public License (CC BY 4.0) file_id: '22163' file_name: crystals-11-00542.pdf file_size: 3042827 relation: main_file title: 'Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response' file_date_updated: 2021-05-13T16:51:41Z funded_apc: '1' has_accepted_license: '1' intvolume: ' 11' isi: '1' language: - iso: eng oa: '1' page: '542' project: - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '52' name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing' publication: Crystals publication_identifier: eissn: - 2073-4352 publication_status: published publisher: MDPI quality_controlled: '1' status: public title: 'Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response' type: journal_article user_id: '171' volume: 11 year: '2021' ... --- _id: '22960' abstract: - lang: eng text: We perform a theoretical analysis of the structural and electronic properties of sodium potassium niobate K1-xNaxNbO3 in the orthorhombic room-temperature phase, based on density-functional theory in combination with the supercell approach. Our results for x=0 and x=0.5 are in very good agreement with experimental measurements and establish that the lattice parameters decrease linearly with increasing Na contents, disproving earlier theoretical studies based on the virtual-crystal approximation that claimed a highly nonlinear behavior with a significant structural distortion and volume reduction in K0.5Na0.5NbO3 compared to both end members of the solid solution. Furthermore, we find that the electronic band gap varies very little between x=0 and x=0.5, reflecting the small changes in the lattice parameters. article_number: '169' article_type: original author: - first_name: Nithin full_name: Bidaraguppe Ramesh, Nithin id: '70064' last_name: Bidaraguppe Ramesh - first_name: Falko full_name: Schmidt, Falko id: '35251' last_name: Schmidt orcid: 0000-0002-5071-5528 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Bidaraguppe Ramesh N, Schmidt F, Schindlmayr A. Lattice parameters and electronic band gap of orthorhombic potassium sodium niobate K0.5Na0.5NbO3 from density-functional theory. The European Physical Journal B. 2021;94(8). doi:10.1140/epjb/s10051-021-00179-8 apa: Bidaraguppe Ramesh, N., Schmidt, F., & Schindlmayr, A. (2021). Lattice parameters and electronic band gap of orthorhombic potassium sodium niobate K0.5Na0.5NbO3 from density-functional theory. The European Physical Journal B, 94(8), Article 169. https://doi.org/10.1140/epjb/s10051-021-00179-8 bibtex: '@article{Bidaraguppe Ramesh_Schmidt_Schindlmayr_2021, title={Lattice parameters and electronic band gap of orthorhombic potassium sodium niobate K0.5Na0.5NbO3 from density-functional theory}, volume={94}, DOI={10.1140/epjb/s10051-021-00179-8}, number={8169}, journal={The European Physical Journal B}, publisher={EDP Sciences, Società Italiana di Fisica and Springer}, author={Bidaraguppe Ramesh, Nithin and Schmidt, Falko and Schindlmayr, Arno}, year={2021} }' chicago: Bidaraguppe Ramesh, Nithin, Falko Schmidt, and Arno Schindlmayr. “Lattice Parameters and Electronic Band Gap of Orthorhombic Potassium Sodium Niobate K0.5Na0.5NbO3 from Density-Functional Theory.” The European Physical Journal B 94, no. 8 (2021). https://doi.org/10.1140/epjb/s10051-021-00179-8. ieee: 'N. Bidaraguppe Ramesh, F. Schmidt, and A. Schindlmayr, “Lattice parameters and electronic band gap of orthorhombic potassium sodium niobate K0.5Na0.5NbO3 from density-functional theory,” The European Physical Journal B, vol. 94, no. 8, Art. no. 169, 2021, doi: 10.1140/epjb/s10051-021-00179-8.' mla: Bidaraguppe Ramesh, Nithin, et al. “Lattice Parameters and Electronic Band Gap of Orthorhombic Potassium Sodium Niobate K0.5Na0.5NbO3 from Density-Functional Theory.” The European Physical Journal B, vol. 94, no. 8, 169, EDP Sciences, Società Italiana di Fisica and Springer, 2021, doi:10.1140/epjb/s10051-021-00179-8. short: N. Bidaraguppe Ramesh, F. Schmidt, A. Schindlmayr, The European Physical Journal B 94 (2021). date_created: 2021-08-08T21:21:42Z date_updated: 2023-04-20T14:56:25Z ddc: - '530' department: - _id: '296' - _id: '230' - _id: '429' - _id: '15' - _id: '170' - _id: '35' doi: 10.1140/epjb/s10051-021-00179-8 external_id: isi: - '000687163200002' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2021-09-02T08:05:06Z date_updated: 2021-09-02T08:05:06Z description: Creative Commons Attribution 4.0 International Public License (CC BY 4.0) file_id: '23679' file_name: BidaraguppeRamesh2021_Article_LatticeParametersAndElectronic.pdf file_size: 850389 relation: main_file title: Lattice parameters and electronic bandgap of orthorhombic potassium sodium niobate K0.5Na0.5NbO3 from density-functional theory file_date_updated: 2021-09-02T08:05:06Z has_accepted_license: '1' intvolume: ' 94' isi: '1' issue: '8' language: - iso: eng oa: '1' project: - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 publication: The European Physical Journal B publication_identifier: eissn: - 1434-6036 issn: - 1434-6028 publication_status: published publisher: EDP Sciences, Società Italiana di Fisica and Springer quality_controlled: '1' status: public title: Lattice parameters and electronic band gap of orthorhombic potassium sodium niobate K0.5Na0.5NbO3 from density-functional theory type: journal_article user_id: '16199' volume: 94 year: '2021' ... --- _id: '22761' article_number: '039901' author: - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Friedrich C, Blügel S, Schindlmayr A. Erratum: Efficient implementation of the GW approximation within the all-electron FLAPW method [Phys. Rev. B 81, 125102 (2010)]. Physical Review B. 2021;104(3). doi:10.1103/PhysRevB.104.039901' apa: 'Friedrich, C., Blügel, S., & Schindlmayr, A. (2021). Erratum: Efficient implementation of the GW approximation within the all-electron FLAPW method [Phys. Rev. B 81, 125102 (2010)]. Physical Review B, 104(3), Article 039901. https://doi.org/10.1103/PhysRevB.104.039901' bibtex: '@article{Friedrich_Blügel_Schindlmayr_2021, title={Erratum: Efficient implementation of the GW approximation within the all-electron FLAPW method [Phys. Rev. B 81, 125102 (2010)]}, volume={104}, DOI={10.1103/PhysRevB.104.039901}, number={3039901}, journal={Physical Review B}, publisher={American Physical Society}, author={Friedrich, Christoph and Blügel, Stefan and Schindlmayr, Arno}, year={2021} }' chicago: 'Friedrich, Christoph, Stefan Blügel, and Arno Schindlmayr. “Erratum: Efficient Implementation of the GW Approximation within the All-Electron FLAPW Method [Phys. Rev. B 81, 125102 (2010)].” Physical Review B 104, no. 3 (2021). https://doi.org/10.1103/PhysRevB.104.039901.' ieee: 'C. Friedrich, S. Blügel, and A. Schindlmayr, “Erratum: Efficient implementation of the GW approximation within the all-electron FLAPW method [Phys. Rev. B 81, 125102 (2010)],” Physical Review B, vol. 104, no. 3, Art. no. 039901, 2021, doi: 10.1103/PhysRevB.104.039901.' mla: 'Friedrich, Christoph, et al. “Erratum: Efficient Implementation of the GW Approximation within the All-Electron FLAPW Method [Phys. Rev. B 81, 125102 (2010)].” Physical Review B, vol. 104, no. 3, 039901, American Physical Society, 2021, doi:10.1103/PhysRevB.104.039901.' short: C. Friedrich, S. Blügel, A. Schindlmayr, Physical Review B 104 (2021). date_created: 2021-07-15T19:59:00Z date_updated: 2023-04-20T14:57:09Z ddc: - '530' department: - _id: '296' - _id: '15' - _id: '170' doi: 10.1103/PhysRevB.104.039901 external_id: isi: - '000671587300006' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2021-07-15T20:16:55Z date_updated: 2021-07-15T20:16:55Z description: © 2021 American Physical Society file_id: '22763' file_name: PhysRevB.104.039901.pdf file_size: 180926 relation: main_file title: 'Erratum: Efficient implementation of the GW approximation within the all-electron FLAPW method [Phys. Rev. B 81, 125102 (2010)]' file_date_updated: 2021-07-15T20:16:55Z has_accepted_license: '1' intvolume: ' 104' isi: '1' issue: '3' language: - iso: eng oa: '1' publication: Physical Review B publication_identifier: eissn: - 2469-9969 issn: - 2469-9950 publication_status: published publisher: American Physical Society quality_controlled: '1' related_material: record: - id: '18558' relation: other status: public status: public title: 'Erratum: Efficient implementation of the GW approximation within the all-electron FLAPW method [Phys. Rev. B 81, 125102 (2010)]' type: journal_article user_id: '16199' volume: 104 year: '2021' ... --- _id: '23418' abstract: - lang: eng text: Density-functional theory within a Berry-phase formulation of the dynamical polarization is used to determine the second-order susceptibility χ(2) of lithium niobate (LiNbO3). Defect trapped polarons and bipolarons are found to strongly enhance the nonlinear susceptibility of the material, in particular if localized at NbV–VLi defect pairs. This is essentially a consequence of the polaronic excitation resulting in relaxation-induced gap states. The occupation of these levels leads to strongly enhanced χ(2) coefficients and allows for the spatial and transient modification of the second-harmonic generation of macroscopic samples. article_type: original author: - first_name: Agnieszka L. full_name: Kozub, Agnieszka L. id: '77566' last_name: Kozub orcid: https://orcid.org/0000-0001-6584-0201 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann orcid: 0000-0002-4476-223X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 citation: ama: Kozub AL, Schindlmayr A, Gerstmann U, Schmidt WG. Polaronic enhancement of second-harmonic generation in lithium niobate. Physical Review B. 2021;104:174110. doi:10.1103/PhysRevB.104.174110 apa: Kozub, A. L., Schindlmayr, A., Gerstmann, U., & Schmidt, W. G. (2021). Polaronic enhancement of second-harmonic generation in lithium niobate. Physical Review B, 104, 174110. https://doi.org/10.1103/PhysRevB.104.174110 bibtex: '@article{Kozub_Schindlmayr_Gerstmann_Schmidt_2021, title={Polaronic enhancement of second-harmonic generation in lithium niobate}, volume={104}, DOI={10.1103/PhysRevB.104.174110}, journal={Physical Review B}, publisher={American Physical Society}, author={Kozub, Agnieszka L. and Schindlmayr, Arno and Gerstmann, Uwe and Schmidt, Wolf Gero}, year={2021}, pages={174110} }' chicago: 'Kozub, Agnieszka L., Arno Schindlmayr, Uwe Gerstmann, and Wolf Gero Schmidt. “Polaronic Enhancement of Second-Harmonic Generation in Lithium Niobate.” Physical Review B 104 (2021): 174110. https://doi.org/10.1103/PhysRevB.104.174110.' ieee: 'A. L. Kozub, A. Schindlmayr, U. Gerstmann, and W. G. Schmidt, “Polaronic enhancement of second-harmonic generation in lithium niobate,” Physical Review B, vol. 104, p. 174110, 2021, doi: 10.1103/PhysRevB.104.174110.' mla: Kozub, Agnieszka L., et al. “Polaronic Enhancement of Second-Harmonic Generation in Lithium Niobate.” Physical Review B, vol. 104, American Physical Society, 2021, p. 174110, doi:10.1103/PhysRevB.104.174110. short: A.L. Kozub, A. Schindlmayr, U. Gerstmann, W.G. Schmidt, Physical Review B 104 (2021) 174110. date_created: 2021-08-16T19:09:46Z date_updated: 2023-04-21T11:15:30Z ddc: - '530' department: - _id: '296' - _id: '230' - _id: '429' - _id: '295' - _id: '15' - _id: '170' - _id: '790' doi: 10.1103/PhysRevB.104.174110 external_id: arxiv: - '2106.01145' isi: - '000720931400007' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2021-11-18T20:49:19Z date_updated: 2021-11-18T20:49:19Z description: © 2021 American Physical Society file_id: '27577' file_name: PhysRevB.104.174110.pdf file_size: 804012 relation: main_file title: Polaronic enhancement of second-harmonic generation in lithium niobate file_date_updated: 2021-11-18T20:49:19Z has_accepted_license: '1' intvolume: ' 104' isi: '1' language: - iso: eng oa: '1' page: '174110' project: - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 - _id: '52' name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing' publication: Physical Review B publication_identifier: eissn: - 2469-9969 issn: - 2469-9950 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: Polaronic enhancement of second-harmonic generation in lithium niobate type: journal_article user_id: '171' volume: 104 year: '2021' ... --- _id: '19190' abstract: - lang: eng text: "Polarons in dielectric crystals play a crucial role for applications in integrated electronics and optoelectronics. In this work, we use density-functional theory and Green's function methods to explore the microscopic structure and spectroscopic signatures of electron polarons in lithium niobate (LiNbO3). Total-energy calculations and the comparison of calculated electron paramagnetic resonance data with available measurements reveal the formation of bound \r\npolarons at Nb_Li antisite defects with a quasi-Jahn-Teller distorted, tilted configuration. The defect-formation energies further indicate that (bi)polarons may form not only at \r\nNb_Li antisites but also at structures where the antisite Nb atom moves into a neighboring empty oxygen octahedron. Based on these structure models, and on the calculated charge-transition levels and potential-energy barriers, we propose two mechanisms for the optical and thermal splitting of bipolarons, which provide a natural explanation for the reported two-path recombination of bipolarons. Optical-response calculations based on the Bethe-Salpeter equation, in combination with available experimental data and new measurements of the optical absorption spectrum, further corroborate the geometries proposed here for free and defect-bound (bi)polarons." article_number: '043002' article_type: original author: - first_name: Falko full_name: Schmidt, Falko id: '35251' last_name: Schmidt orcid: 0000-0002-5071-5528 - first_name: Agnieszka L. full_name: Kozub, Agnieszka L. id: '77566' last_name: Kozub orcid: https://orcid.org/0000-0001-6584-0201 - first_name: Timur full_name: Biktagirov, Timur id: '65612' last_name: Biktagirov - first_name: Christof full_name: Eigner, Christof id: '13244' last_name: Eigner orcid: https://orcid.org/0000-0002-5693-3083 - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann orcid: 0000-0002-4476-223X citation: ama: 'Schmidt F, Kozub AL, Biktagirov T, et al. Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations. Physical Review Research. 2020;2(4). doi:10.1103/PhysRevResearch.2.043002' apa: 'Schmidt, F., Kozub, A. L., Biktagirov, T., Eigner, C., Silberhorn, C., Schindlmayr, A., Schmidt, W. G., & Gerstmann, U. (2020). Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations. Physical Review Research, 2(4), Article 043002. https://doi.org/10.1103/PhysRevResearch.2.043002' bibtex: '@article{Schmidt_Kozub_Biktagirov_Eigner_Silberhorn_Schindlmayr_Schmidt_Gerstmann_2020, title={Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations}, volume={2}, DOI={10.1103/PhysRevResearch.2.043002}, number={4043002}, journal={Physical Review Research}, publisher={American Physical Society}, author={Schmidt, Falko and Kozub, Agnieszka L. and Biktagirov, Timur and Eigner, Christof and Silberhorn, Christine and Schindlmayr, Arno and Schmidt, Wolf Gero and Gerstmann, Uwe}, year={2020} }' chicago: 'Schmidt, Falko, Agnieszka L. Kozub, Timur Biktagirov, Christof Eigner, Christine Silberhorn, Arno Schindlmayr, Wolf Gero Schmidt, and Uwe Gerstmann. “Free and Defect-Bound (Bi)Polarons in LiNbO3: Atomic Structure and Spectroscopic Signatures from Ab Initio Calculations.” Physical Review Research 2, no. 4 (2020). https://doi.org/10.1103/PhysRevResearch.2.043002.' ieee: 'F. Schmidt et al., “Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations,” Physical Review Research, vol. 2, no. 4, Art. no. 043002, 2020, doi: 10.1103/PhysRevResearch.2.043002.' mla: 'Schmidt, Falko, et al. “Free and Defect-Bound (Bi)Polarons in LiNbO3: Atomic Structure and Spectroscopic Signatures from Ab Initio Calculations.” Physical Review Research, vol. 2, no. 4, 043002, American Physical Society, 2020, doi:10.1103/PhysRevResearch.2.043002.' short: F. Schmidt, A.L. Kozub, T. Biktagirov, C. Eigner, C. Silberhorn, A. Schindlmayr, W.G. Schmidt, U. Gerstmann, Physical Review Research 2 (2020). date_created: 2020-09-09T09:35:21Z date_updated: 2023-04-20T16:06:21Z ddc: - '530' department: - _id: '296' - _id: '230' - _id: '429' - _id: '295' - _id: '288' - _id: '15' - _id: '170' - _id: '35' - _id: '790' doi: 10.1103/PhysRevResearch.2.043002 external_id: isi: - '000604206300002' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-10-02T07:27:38Z date_updated: 2020-10-02T07:37:24Z description: Creative Commons Attribution 4.0 International Public License (CC BY 4.0) file_id: '19843' file_name: PhysRevResearch.2.043002.pdf file_size: 1955183 relation: main_file title: 'Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations' file_date_updated: 2020-10-02T07:37:24Z has_accepted_license: '1' intvolume: ' 2' isi: '1' issue: '4' language: - iso: eng oa: '1' project: - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '52' name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing' publication: Physical Review Research publication_identifier: eissn: - 2643-1564 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: 'Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations' type: journal_article user_id: '16199' volume: 2 year: '2020' ... --- _id: '10014' abstract: - lang: eng text: The cubic, tetragonal, and orthorhombic phase of potassium niobate (KNbO3) are studied based on density-functional theory. Starting from the relaxed atomic geometries, we analyze the influence of self-energy corrections on the electronic band structure within the GW approximation. We find that quasiparticle shifts widen the direct (indirect) band gap by 1.21 (1.44), 1.58 (1.55), and 1.67 (1.64) eV for the cubic, tetragonal, and orthorhombic phase, respectively. By solving the Bethe-Salpeter equation, we obtain the linear dielectric function with excitonic and local-field effects, which turn out to be essential for good agreement with experimental data. From our results, we extract an exciton binding energy of 0.6, 0.5, and 0.5 eV for the cubic, tetragonal, and orthorhombic phase, respectively. Furthermore, we investigate the nonlinear second-harmonic generation (SHG) both theoretically and experimentally. The frequency-dependent second-order polarization tensor of orthorhombic KNbO3 is measured for incoming photon energies between 1.2 and 1.6 eV. In addition, calculations within the independent-(quasi)particle approximation are performed for the tetragonal and orthorhombic phase. The novel experimental data are in excellent agreement with the quasiparticle calculations and resolve persistent discrepancies between earlier experimental measurements and ab initio results reported in the literature. article_number: '054401' article_type: original author: - first_name: Falko full_name: Schmidt, Falko id: '35251' last_name: Schmidt orcid: 0000-0002-5071-5528 - first_name: Arthur full_name: Riefer, Arthur last_name: Riefer - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Mirco full_name: Imlau, Mirco last_name: Imlau - first_name: Florian full_name: Dobener, Florian last_name: Dobener - first_name: Nils full_name: Mengel, Nils last_name: Mengel - first_name: Sangam full_name: Chatterjee, Sangam last_name: Chatterjee - first_name: Simone full_name: Sanna, Simone last_name: Sanna citation: ama: Schmidt F, Riefer A, Schmidt WG, et al. Quasiparticle and excitonic effects in the optical response of KNbO3. Physical Review Materials. 2019;3(5). doi:10.1103/PhysRevMaterials.3.054401 apa: Schmidt, F., Riefer, A., Schmidt, W. G., Schindlmayr, A., Imlau, M., Dobener, F., Mengel, N., Chatterjee, S., & Sanna, S. (2019). Quasiparticle and excitonic effects in the optical response of KNbO3. Physical Review Materials, 3(5), Article 054401. https://doi.org/10.1103/PhysRevMaterials.3.054401 bibtex: '@article{Schmidt_Riefer_Schmidt_Schindlmayr_Imlau_Dobener_Mengel_Chatterjee_Sanna_2019, title={Quasiparticle and excitonic effects in the optical response of KNbO3}, volume={3}, DOI={10.1103/PhysRevMaterials.3.054401}, number={5054401}, journal={Physical Review Materials}, publisher={American Physical Society}, author={Schmidt, Falko and Riefer, Arthur and Schmidt, Wolf Gero and Schindlmayr, Arno and Imlau, Mirco and Dobener, Florian and Mengel, Nils and Chatterjee, Sangam and Sanna, Simone}, year={2019} }' chicago: Schmidt, Falko, Arthur Riefer, Wolf Gero Schmidt, Arno Schindlmayr, Mirco Imlau, Florian Dobener, Nils Mengel, Sangam Chatterjee, and Simone Sanna. “Quasiparticle and Excitonic Effects in the Optical Response of KNbO3.” Physical Review Materials 3, no. 5 (2019). https://doi.org/10.1103/PhysRevMaterials.3.054401. ieee: 'F. Schmidt et al., “Quasiparticle and excitonic effects in the optical response of KNbO3,” Physical Review Materials, vol. 3, no. 5, Art. no. 054401, 2019, doi: 10.1103/PhysRevMaterials.3.054401.' mla: Schmidt, Falko, et al. “Quasiparticle and Excitonic Effects in the Optical Response of KNbO3.” Physical Review Materials, vol. 3, no. 5, 054401, American Physical Society, 2019, doi:10.1103/PhysRevMaterials.3.054401. short: F. Schmidt, A. Riefer, W.G. Schmidt, A. Schindlmayr, M. Imlau, F. Dobener, N. Mengel, S. Chatterjee, S. Sanna, Physical Review Materials 3 (2019). date_created: 2019-05-29T06:55:29Z date_updated: 2023-04-20T14:20:33Z ddc: - '530' department: - _id: '295' - _id: '296' - _id: '230' - _id: '429' - _id: '170' - _id: '35' doi: 10.1103/PhysRevMaterials.3.054401 external_id: isi: - '000467044000003' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-27T19:05:54Z date_updated: 2020-08-30T14:34:33Z description: © 2019 American Physical Society file_id: '18465' file_name: PhysRevMaterials.3.054401.pdf file_size: 1949504 relation: main_file title: Quasiparticle and excitonic effects in the optical response of KNbO3 file_date_updated: 2020-08-30T14:34:33Z has_accepted_license: '1' intvolume: ' 3' isi: '1' issue: '5' language: - iso: eng oa: '1' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 - _id: '52' name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing' publication: Physical Review Materials publication_identifier: eissn: - 2475-9953 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: Quasiparticle and excitonic effects in the optical response of KNbO3 type: journal_article user_id: '16199' volume: 3 year: '2019' ... --- _id: '13365' abstract: - lang: eng text: 'The KTiOPO4 (KTP) band structure and dielectric function are calculated on various levels of theory starting from density-functional calculations. Within the independent-particle approximation an electronic transport gap of 2.97 eV is obtained that widens to about 5.23 eV when quasiparticle effects are included using the GW approximation. The optical response is shown to be strongly anisotropic due to (i) the slight asymmetry of the TiO6 octahedra in the (001) plane and (ii) their anisotropic distribution along the [001] and [100] directions. In addition, excitonic effects are very important: The solution of the Bethe–Salpeter equation indicates exciton binding energies of the order of 1.5 eV. Calculations that include both quasiparticle and excitonic effects are in good agreement with the measured reflectivity.' article_type: original author: - first_name: Sergej full_name: Neufeld, Sergej id: '23261' last_name: Neufeld - first_name: Adriana full_name: Bocchini, Adriana id: '58349' last_name: Bocchini orcid: https://orcid.org/0000-0002-2134-3075 - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann orcid: 0000-0002-4476-223X - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 citation: ama: 'Neufeld S, Bocchini A, Gerstmann U, Schindlmayr A, Schmidt WG. Potassium titanyl phosphate (KTP) quasiparticle energies and optical response. Journal of Physics: Materials. 2019;2:045003. doi:10.1088/2515-7639/ab29ba' apa: 'Neufeld, S., Bocchini, A., Gerstmann, U., Schindlmayr, A., & Schmidt, W. G. (2019). Potassium titanyl phosphate (KTP) quasiparticle energies and optical response. Journal of Physics: Materials, 2, 045003. https://doi.org/10.1088/2515-7639/ab29ba' bibtex: '@article{Neufeld_Bocchini_Gerstmann_Schindlmayr_Schmidt_2019, title={Potassium titanyl phosphate (KTP) quasiparticle energies and optical response}, volume={2}, DOI={10.1088/2515-7639/ab29ba}, journal={Journal of Physics: Materials}, publisher={IOP Publishing}, author={Neufeld, Sergej and Bocchini, Adriana and Gerstmann, Uwe and Schindlmayr, Arno and Schmidt, Wolf Gero}, year={2019}, pages={045003} }' chicago: 'Neufeld, Sergej, Adriana Bocchini, Uwe Gerstmann, Arno Schindlmayr, and Wolf Gero Schmidt. “Potassium Titanyl Phosphate (KTP) Quasiparticle Energies and Optical Response.” Journal of Physics: Materials 2 (2019): 045003. https://doi.org/10.1088/2515-7639/ab29ba.' ieee: 'S. Neufeld, A. Bocchini, U. Gerstmann, A. Schindlmayr, and W. G. Schmidt, “Potassium titanyl phosphate (KTP) quasiparticle energies and optical response,” Journal of Physics: Materials, vol. 2, p. 045003, 2019, doi: 10.1088/2515-7639/ab29ba.' mla: 'Neufeld, Sergej, et al. “Potassium Titanyl Phosphate (KTP) Quasiparticle Energies and Optical Response.” Journal of Physics: Materials, vol. 2, IOP Publishing, 2019, p. 045003, doi:10.1088/2515-7639/ab29ba.' short: 'S. Neufeld, A. Bocchini, U. Gerstmann, A. Schindlmayr, W.G. Schmidt, Journal of Physics: Materials 2 (2019) 045003.' date_created: 2019-09-19T14:34:16Z date_updated: 2023-04-21T11:36:12Z ddc: - '530' department: - _id: '296' - _id: '295' - _id: '230' - _id: '429' - _id: '170' - _id: '35' doi: 10.1088/2515-7639/ab29ba external_id: isi: - '000560410300003' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T09:07:18Z date_updated: 2020-08-30T14:29:27Z description: Creative Commons Attribution 3.0 Unported Public License (CC BY 3.0) file_id: '18535' file_name: Neufeld_2019_J._Phys._Mater._2_045003.pdf file_size: 1481174 relation: main_file title: Potassium titanyl phosphate (KTP) quasiparticle energies and optical response file_date_updated: 2020-08-30T14:29:27Z has_accepted_license: '1' intvolume: ' 2' isi: '1' language: - iso: eng oa: '1' page: '045003' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 - _id: '52' name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing' publication: 'Journal of Physics: Materials' publication_identifier: eissn: - 2515-7639 publication_status: published publisher: IOP Publishing quality_controlled: '1' status: public title: Potassium titanyl phosphate (KTP) quasiparticle energies and optical response type: journal_article user_id: '171' volume: 2 year: '2019' ... --- _id: '18466' abstract: - lang: eng text: The transverse dynamic spin susceptibility is a correlation function that yields exact information about spin excitations in systems with a collinear magnetic ground state, including collective spin-wave modes. In an ab initio context, it may be calculated within many-body perturbation theory or time-dependent density-functional theory, but the quantitative accuracy is currently limited by the available functionals for exchange and correlation in dynamically evolving systems. To circumvent this limitation, the spin susceptibility is here alternatively formulated as the solution of an initial-value problem. In this way, the challenge of accurately describing exchange and correlation in many-electron systems is shifted to the stationary initial state, which is much better understood. The proposed scheme further requires the choice of an auxiliary basis set, which determines the speed of convergence but always allows systematic convergence in practical implementations. article_number: '3732892' article_type: original author: - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Schindlmayr A. Exact formulation of the transverse dynamic spin susceptibility as an initial-value problem. Advances in Mathematical Physics. 2018;2018. doi:10.1155/2018/3732892 apa: Schindlmayr, A. (2018). Exact formulation of the transverse dynamic spin susceptibility as an initial-value problem. Advances in Mathematical Physics, 2018. https://doi.org/10.1155/2018/3732892 bibtex: '@article{Schindlmayr_2018, title={Exact formulation of the transverse dynamic spin susceptibility as an initial-value problem}, volume={2018}, DOI={10.1155/2018/3732892}, number={3732892}, journal={Advances in Mathematical Physics}, publisher={Hindawi}, author={Schindlmayr, Arno}, year={2018} }' chicago: Schindlmayr, Arno. “Exact Formulation of the Transverse Dynamic Spin Susceptibility as an Initial-Value Problem.” Advances in Mathematical Physics 2018 (2018). https://doi.org/10.1155/2018/3732892. ieee: A. Schindlmayr, “Exact formulation of the transverse dynamic spin susceptibility as an initial-value problem,” Advances in Mathematical Physics, vol. 2018, 2018. mla: Schindlmayr, Arno. “Exact Formulation of the Transverse Dynamic Spin Susceptibility as an Initial-Value Problem.” Advances in Mathematical Physics, vol. 2018, 3732892, Hindawi, 2018, doi:10.1155/2018/3732892. short: A. Schindlmayr, Advances in Mathematical Physics 2018 (2018). date_created: 2020-08-27T19:18:34Z date_updated: 2022-01-06T06:53:33Z ddc: - '530' department: - _id: '296' doi: 10.1155/2018/3732892 external_id: isi: - '000422773000001' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T09:18:25Z date_updated: 2020-08-30T14:31:38Z description: Creative Commons Attribution 4.0 International Public License (CC BY 4.0) file_id: '18537' file_name: 3732892.pdf file_size: 294410 relation: main_file title: Exact formulation of the transverse dynamic spin susceptibility as an initial-value problem file_date_updated: 2020-08-30T14:31:38Z has_accepted_license: '1' intvolume: ' 2018' isi: '1' language: - iso: eng oa: '1' publication: Advances in Mathematical Physics publication_identifier: eissn: - 1687-9139 issn: - 1687-9120 publication_status: published publisher: Hindawi quality_controlled: '1' status: public title: Exact formulation of the transverse dynamic spin susceptibility as an initial-value problem type: journal_article user_id: '458' volume: 2018 year: '2018' ... --- _id: '13410' article_number: '019902' author: - first_name: Michael full_name: Friedrich, Michael last_name: Friedrich - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Simone full_name: Sanna, Simone last_name: Sanna citation: ama: 'Friedrich M, Schmidt WG, Schindlmayr A, Sanna S. Erratum: Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory [Phys. Rev. Materials 1, 034401 (2017)]. Physical Review Materials. 2018;2(1). doi:10.1103/PhysRevMaterials.2.019902' apa: 'Friedrich, M., Schmidt, W. G., Schindlmayr, A., & Sanna, S. (2018). Erratum: Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory [Phys. Rev. Materials 1, 034401 (2017)]. Physical Review Materials, 2(1). https://doi.org/10.1103/PhysRevMaterials.2.019902' bibtex: '@article{Friedrich_Schmidt_Schindlmayr_Sanna_2018, title={Erratum: Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory [Phys. Rev. Materials 1, 034401 (2017)]}, volume={2}, DOI={10.1103/PhysRevMaterials.2.019902}, number={1019902}, journal={Physical Review Materials}, publisher={American Physical Society}, author={Friedrich, Michael and Schmidt, Wolf Gero and Schindlmayr, Arno and Sanna, Simone}, year={2018} }' chicago: 'Friedrich, Michael, Wolf Gero Schmidt, Arno Schindlmayr, and Simone Sanna. “Erratum: Optical Properties of Titanium-Doped Lithium Niobate from Time-Dependent Density-Functional Theory [Phys. Rev. Materials 1, 034401 (2017)].” Physical Review Materials 2, no. 1 (2018). https://doi.org/10.1103/PhysRevMaterials.2.019902.' ieee: 'M. Friedrich, W. G. Schmidt, A. Schindlmayr, and S. Sanna, “Erratum: Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory [Phys. Rev. Materials 1, 034401 (2017)],” Physical Review Materials, vol. 2, no. 1, 2018.' mla: 'Friedrich, Michael, et al. “Erratum: Optical Properties of Titanium-Doped Lithium Niobate from Time-Dependent Density-Functional Theory [Phys. Rev. Materials 1, 034401 (2017)].” Physical Review Materials, vol. 2, no. 1, 019902, American Physical Society, 2018, doi:10.1103/PhysRevMaterials.2.019902.' short: M. Friedrich, W.G. Schmidt, A. Schindlmayr, S. Sanna, Physical Review Materials 2 (2018). date_created: 2019-09-20T11:28:23Z date_updated: 2022-01-06T06:51:35Z ddc: - '530' department: - _id: '295' - _id: '296' - _id: '230' - _id: '429' doi: 10.1103/PhysRevMaterials.2.019902 external_id: isi: - '000419778500006' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T09:11:59Z date_updated: 2020-08-30T14:34:54Z description: © 2018 American Physical Society file_id: '18536' file_name: PhysRevMaterials.2.019902.pdf file_size: 178961 relation: main_file title: 'Erratum: Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory [Phys. Rev. Materials 1, 034401 (2017)]' file_date_updated: 2020-08-30T14:34:54Z has_accepted_license: '1' intvolume: ' 2' isi: '1' issue: '1' language: - iso: eng oa: '1' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '68' name: TRR 142 - Subproject B3 - _id: '69' name: TRR 142 - Subproject B4 publication: Physical Review Materials publication_identifier: eissn: - 2475-9953 publication_status: published publisher: American Physical Society quality_controlled: '1' related_material: record: - id: '10021' relation: other status: public status: public title: 'Erratum: Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory [Phys. Rev. Materials 1, 034401 (2017)]' type: journal_article user_id: '458' volume: 2 year: '2018' ... --- _id: '7481' abstract: - lang: eng text: The electronic band structures of hexagonal ZnO and cubic ZnS, ZnSe, and ZnTe compounds are determined within hybrid-density-functional theory and quasiparticle calculations. It is found that the band-edge energies calculated on the G0W0 (Zn chalcogenides) or GW (ZnO) level of theory agree well with experiment, while fully self-consistent QSGW calculations are required for the correct description of the Zn 3d bands. The quasiparticle band structures are used to calculate the linear response and second-harmonic-generation (SHG) spectra of the Zn–VI compounds. Excitonic effects in the optical absorption are accounted for within the Bethe–Salpeter approach. The calculated spectra are discussed in the context of previous experimental data and present SHG measurements for ZnO. article_number: '215702' article_type: original author: - first_name: Arthur full_name: Riefer, Arthur last_name: Riefer - first_name: Nils full_name: Weber, Nils last_name: Weber - first_name: Johannes full_name: Mund, Johannes last_name: Mund - first_name: Dmitri R. full_name: Yakovlev, Dmitri R. last_name: Yakovlev - first_name: Manfred full_name: Bayer, Manfred last_name: Bayer - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Cedrik full_name: Meier, Cedrik id: '20798' last_name: Meier orcid: https://orcid.org/0000-0002-3787-3572 - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 citation: ama: 'Riefer A, Weber N, Mund J, et al. Zn–VI quasiparticle gaps and optical spectra from many-body calculations. Journal of Physics: Condensed Matter. 2017;29(21). doi:10.1088/1361-648x/aa6b2a' apa: 'Riefer, A., Weber, N., Mund, J., Yakovlev, D. R., Bayer, M., Schindlmayr, A., … Schmidt, W. G. (2017). Zn–VI quasiparticle gaps and optical spectra from many-body calculations. Journal of Physics: Condensed Matter, 29(21). https://doi.org/10.1088/1361-648x/aa6b2a' bibtex: '@article{Riefer_Weber_Mund_Yakovlev_Bayer_Schindlmayr_Meier_Schmidt_2017, title={Zn–VI quasiparticle gaps and optical spectra from many-body calculations}, volume={29}, DOI={10.1088/1361-648x/aa6b2a}, number={21215702}, journal={Journal of Physics: Condensed Matter}, publisher={IOP Publishing}, author={Riefer, Arthur and Weber, Nils and Mund, Johannes and Yakovlev, Dmitri R. and Bayer, Manfred and Schindlmayr, Arno and Meier, Cedrik and Schmidt, Wolf Gero}, year={2017} }' chicago: 'Riefer, Arthur, Nils Weber, Johannes Mund, Dmitri R. Yakovlev, Manfred Bayer, Arno Schindlmayr, Cedrik Meier, and Wolf Gero Schmidt. “Zn–VI Quasiparticle Gaps and Optical Spectra from Many-Body Calculations.” Journal of Physics: Condensed Matter 29, no. 21 (2017). https://doi.org/10.1088/1361-648x/aa6b2a.' ieee: 'A. Riefer et al., “Zn–VI quasiparticle gaps and optical spectra from many-body calculations,” Journal of Physics: Condensed Matter, vol. 29, no. 21, 2017.' mla: 'Riefer, Arthur, et al. “Zn–VI Quasiparticle Gaps and Optical Spectra from Many-Body Calculations.” Journal of Physics: Condensed Matter, vol. 29, no. 21, 215702, IOP Publishing, 2017, doi:10.1088/1361-648x/aa6b2a.' short: 'A. Riefer, N. Weber, J. Mund, D.R. Yakovlev, M. Bayer, A. Schindlmayr, C. Meier, W.G. Schmidt, Journal of Physics: Condensed Matter 29 (2017).' date_created: 2019-02-04T13:46:58Z date_updated: 2022-01-06T07:03:39Z ddc: - '530' department: - _id: '287' - _id: '295' - _id: '296' - _id: '230' - _id: '429' doi: 10.1088/1361-648x/aa6b2a external_id: isi: - '000400093100001' pmid: - '28374685' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T14:01:15Z date_updated: 2020-08-30T14:34:08Z description: © 2017 IOP Publishing Ltd file_id: '18574' file_name: Riefer_2017_J._Phys. _Condens._Matter_29_215702.pdf file_size: 2551657 relation: main_file title: Zn–VI quasiparticle gaps and optical spectra from many-body calculations file_date_updated: 2020-08-30T14:34:08Z has_accepted_license: '1' intvolume: ' 29' isi: '1' issue: '21' language: - iso: eng pmid: '1' project: - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '66' name: TRR 142 - Subproject B1 - _id: '69' name: TRR 142 - Subproject B4 - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing publication: 'Journal of Physics: Condensed Matter' publication_identifier: eissn: - 1361-648X issn: - 0953-8984 publication_status: published publisher: IOP Publishing quality_controlled: '1' status: public title: Zn–VI quasiparticle gaps and optical spectra from many-body calculations type: journal_article user_id: '458' volume: 29 year: '2017' ... --- _id: '13416' abstract: - lang: eng text: 'The optical properties of congruent lithium niobate are analyzed from first principles. The dielectric function of the material is calculated within time-dependent density-functional theory. The effects of isolated intrinsic defects and defect pairs, including the NbLi4+ antisite and the NbLi4+−NbNb4+ pair, commonly addressed as a bound polaron and bipolaron, respectively, are discussed in detail. In addition, we present further possible realizations of polaronic and bipolaronic systems. The absorption feature around 1.64 eV, ascribed to small bound polarons [O. F. Schirmer et al., J. Phys.: Condens. Matter 21, 123201 (2009)], is nicely reproduced within these models. Among the investigated defects, we find that the presence of bipolarons at bound interstitial-vacancy pairs NbV−VLi can best explain the experimentally observed broad absorption band at 2.5 eV. Our results provide a microscopic model for the observed optical spectra and suggest that, besides NbLi antisites and Nb and Li vacancies, Nb interstitials are also formed in congruent lithium-niobate samples.' article_number: '054406' article_type: original author: - first_name: Michael full_name: Friedrich, Michael last_name: Friedrich - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Simone full_name: Sanna, Simone last_name: Sanna citation: ama: Friedrich M, Schmidt WG, Schindlmayr A, Sanna S. Polaron optical absorption in congruent lithium niobate from time-dependent density-functional theory. Physical Review Materials. 2017;1(5). doi:10.1103/PhysRevMaterials.1.054406 apa: Friedrich, M., Schmidt, W. G., Schindlmayr, A., & Sanna, S. (2017). Polaron optical absorption in congruent lithium niobate from time-dependent density-functional theory. Physical Review Materials, 1(5). https://doi.org/10.1103/PhysRevMaterials.1.054406 bibtex: '@article{Friedrich_Schmidt_Schindlmayr_Sanna_2017, title={Polaron optical absorption in congruent lithium niobate from time-dependent density-functional theory}, volume={1}, DOI={10.1103/PhysRevMaterials.1.054406}, number={5054406}, journal={Physical Review Materials}, publisher={American Physical Society}, author={Friedrich, Michael and Schmidt, Wolf Gero and Schindlmayr, Arno and Sanna, Simone}, year={2017} }' chicago: Friedrich, Michael, Wolf Gero Schmidt, Arno Schindlmayr, and Simone Sanna. “Polaron Optical Absorption in Congruent Lithium Niobate from Time-Dependent Density-Functional Theory.” Physical Review Materials 1, no. 5 (2017). https://doi.org/10.1103/PhysRevMaterials.1.054406. ieee: M. Friedrich, W. G. Schmidt, A. Schindlmayr, and S. Sanna, “Polaron optical absorption in congruent lithium niobate from time-dependent density-functional theory,” Physical Review Materials, vol. 1, no. 5, 2017. mla: Friedrich, Michael, et al. “Polaron Optical Absorption in Congruent Lithium Niobate from Time-Dependent Density-Functional Theory.” Physical Review Materials, vol. 1, no. 5, 054406, American Physical Society, 2017, doi:10.1103/PhysRevMaterials.1.054406. short: M. Friedrich, W.G. Schmidt, A. Schindlmayr, S. Sanna, Physical Review Materials 1 (2017). date_created: 2019-09-20T11:54:25Z date_updated: 2022-01-06T06:51:35Z ddc: - '530' department: - _id: '296' - _id: '295' - _id: '230' - _id: '429' doi: 10.1103/PhysRevMaterials.1.054406 external_id: isi: - '000416586100003' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-27T19:43:49Z date_updated: 2020-08-30T14:38:50Z description: © 2017 American Physical Society file_id: '18468' file_name: PhysRevMaterials.1.054406.pdf file_size: 1417182 relation: main_file title: Polaron optical absorption in congruent lithium niobate from time-dependent density-functional theory file_date_updated: 2020-08-30T14:38:50Z has_accepted_license: '1' intvolume: ' 1' isi: '1' issue: '5' language: - iso: eng oa: '1' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '68' name: TRR 142 - Subproject B3 - _id: '69' name: TRR 142 - Subproject B4 publication: Physical Review Materials publication_identifier: eissn: - 2475-9953 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: Polaron optical absorption in congruent lithium niobate from time-dependent density-functional theory type: journal_article user_id: '458' volume: 1 year: '2017' ... --- _id: '10021' abstract: - lang: eng text: The optical properties of pristine and titanium-doped LiNbO3 are modeled from first principles. The dielectric functions are calculated within time-dependent density-functional theory, and a model long-range contribution is employed for the exchange-correlation kernel in order to account for the electron-hole binding. Our study focuses on the influence of substitutional titanium atoms on lithium sites. We show that an increasing titanium concentration enhances the values of the refractive indices and the reflectivity. article_number: '034401' article_type: original author: - first_name: Michael full_name: Friedrich, Michael last_name: Friedrich - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Simone full_name: Sanna, Simone last_name: Sanna citation: ama: Friedrich M, Schmidt WG, Schindlmayr A, Sanna S. Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory. Physical Review Materials. 2017;1(3). doi:10.1103/PhysRevMaterials.1.034401 apa: Friedrich, M., Schmidt, W. G., Schindlmayr, A., & Sanna, S. (2017). Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory. Physical Review Materials, 1(3). https://doi.org/10.1103/PhysRevMaterials.1.034401 bibtex: '@article{Friedrich_Schmidt_Schindlmayr_Sanna_2017, title={Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory}, volume={1}, DOI={10.1103/PhysRevMaterials.1.034401}, number={3034401}, journal={Physical Review Materials}, publisher={American Physical Society}, author={Friedrich, Michael and Schmidt, Wolf Gero and Schindlmayr, Arno and Sanna, Simone}, year={2017} }' chicago: Friedrich, Michael, Wolf Gero Schmidt, Arno Schindlmayr, and Simone Sanna. “Optical Properties of Titanium-Doped Lithium Niobate from Time-Dependent Density-Functional Theory.” Physical Review Materials 1, no. 3 (2017). https://doi.org/10.1103/PhysRevMaterials.1.034401. ieee: M. Friedrich, W. G. Schmidt, A. Schindlmayr, and S. Sanna, “Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory,” Physical Review Materials, vol. 1, no. 3, 2017. mla: Friedrich, Michael, et al. “Optical Properties of Titanium-Doped Lithium Niobate from Time-Dependent Density-Functional Theory.” Physical Review Materials, vol. 1, no. 3, 034401, American Physical Society, 2017, doi:10.1103/PhysRevMaterials.1.034401. short: M. Friedrich, W.G. Schmidt, A. Schindlmayr, S. Sanna, Physical Review Materials 1 (2017). date_created: 2019-05-29T07:42:33Z date_updated: 2022-01-06T06:51:35Z ddc: - '530' department: - _id: '295' - _id: '296' - _id: '230' - _id: '429' doi: 10.1103/PhysRevMaterials.1.034401 external_id: isi: - '000416562300001' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-27T19:39:54Z date_updated: 2020-08-30T14:36:11Z description: © 2017 American Physical Society file_id: '18467' file_name: PhysRevMaterials.1.034401.pdf file_size: 708075 relation: main_file title: Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory file_date_updated: 2020-08-30T14:36:11Z has_accepted_license: '1' intvolume: ' 1' isi: '1' issue: '3' language: - iso: eng oa: '1' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 - _id: '68' name: TRR 142 - Subproject B3 publication: Physical Review Materials publication_identifier: issn: - 2475-9953 publication_status: published publisher: American Physical Society quality_controlled: '1' related_material: record: - id: '13410' relation: other status: public status: public title: Optical properties of titanium-doped lithium niobate from time-dependent density-functional theory type: journal_article user_id: '458' volume: 1 year: '2017' ... --- _id: '10023' abstract: - lang: eng text: We perform a comprehensive theoretical study of the structural and electronic properties of potassium niobate (KNbO3) in the cubic, tetragonal, orthorhombic, monoclinic, and rhombohedral phase, based on density-functional theory. The influence of different parametrizations of the exchange-correlation functional on the investigated properties is analyzed in detail, and the results are compared to available experimental data. We argue that the PBEsol and AM05 generalized gradient approximations as well as the RTPSS meta-generalized gradient approximation yield consistently accurate structural data for both the external and internal degrees of freedom and are overall superior to the local-density approximation or other conventional generalized gradient approximations for the structural characterization of KNbO3. Band-structure calculations using a HSE-type hybrid functional further indicate significant near degeneracies of band-edge states in all phases which are expected to be relevant for the optical response of the material. article_number: '3981317' article_type: original author: - first_name: Falko full_name: Schmidt, Falko id: '35251' last_name: Schmidt orcid: 0000-0002-5071-5528 - first_name: Marc full_name: Landmann, Marc last_name: Landmann - first_name: Eva full_name: Rauls, Eva last_name: Rauls - first_name: Nicola full_name: Argiolas, Nicola last_name: Argiolas - first_name: Simone full_name: Sanna, Simone last_name: Sanna - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Schmidt F, Landmann M, Rauls E, et al. Consistent atomic geometries and electronic structure of five phases of potassium niobate from density-functional theory. Advances in Materials Science and Engineering. 2017;2017. doi:10.1155/2017/3981317 apa: Schmidt, F., Landmann, M., Rauls, E., Argiolas, N., Sanna, S., Schmidt, W. G., & Schindlmayr, A. (2017). Consistent atomic geometries and electronic structure of five phases of potassium niobate from density-functional theory. Advances in Materials Science and Engineering, 2017. https://doi.org/10.1155/2017/3981317 bibtex: '@article{Schmidt_Landmann_Rauls_Argiolas_Sanna_Schmidt_Schindlmayr_2017, title={Consistent atomic geometries and electronic structure of five phases of potassium niobate from density-functional theory}, volume={2017}, DOI={10.1155/2017/3981317}, number={3981317}, journal={Advances in Materials Science and Engineering}, publisher={Hindawi}, author={Schmidt, Falko and Landmann, Marc and Rauls, Eva and Argiolas, Nicola and Sanna, Simone and Schmidt, Wolf Gero and Schindlmayr, Arno}, year={2017} }' chicago: Schmidt, Falko, Marc Landmann, Eva Rauls, Nicola Argiolas, Simone Sanna, Wolf Gero Schmidt, and Arno Schindlmayr. “Consistent Atomic Geometries and Electronic Structure of Five Phases of Potassium Niobate from Density-Functional Theory.” Advances in Materials Science and Engineering 2017 (2017). https://doi.org/10.1155/2017/3981317. ieee: F. Schmidt et al., “Consistent atomic geometries and electronic structure of five phases of potassium niobate from density-functional theory,” Advances in Materials Science and Engineering, vol. 2017, 2017. mla: Schmidt, Falko, et al. “Consistent Atomic Geometries and Electronic Structure of Five Phases of Potassium Niobate from Density-Functional Theory.” Advances in Materials Science and Engineering, vol. 2017, 3981317, Hindawi, 2017, doi:10.1155/2017/3981317. short: F. Schmidt, M. Landmann, E. Rauls, N. Argiolas, S. Sanna, W.G. Schmidt, A. Schindlmayr, Advances in Materials Science and Engineering 2017 (2017). date_created: 2019-05-29T07:48:32Z date_updated: 2022-01-06T06:50:25Z ddc: - '530' department: - _id: '295' - _id: '296' - _id: '230' - _id: '429' doi: 10.1155/2017/3981317 external_id: isi: - '000394873300001' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T09:27:19Z date_updated: 2020-08-30T14:37:31Z description: Creative Commons Attribution 4.0 International Public License (CC BY 4.0) file_id: '18538' file_name: 3981317.pdf file_size: 985948 relation: main_file title: Consistent atomic geometries and electronic structure of five phases of potassium niobate from density-functional theory file_date_updated: 2020-08-30T14:37:31Z has_accepted_license: '1' intvolume: ' 2017' isi: '1' language: - iso: eng oa: '1' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 publication: Advances in Materials Science and Engineering publication_identifier: eissn: - 1687-8442 issn: - 1687-8434 publication_status: published publisher: Hindawi quality_controlled: '1' status: public title: Consistent atomic geometries and electronic structure of five phases of potassium niobate from density-functional theory type: journal_article user_id: '458' volume: 2017 year: '2017' ... --- _id: '10024' abstract: - lang: eng text: The influence of electronic many-body interactions, spin-orbit coupling, and thermal lattice vibrations on the electronic structure of lithium niobate is calculated from first principles. Self-energy calculations in the GW approximation show that the inclusion of self-consistency in the Green function G and the screened Coulomb potential W opens the band gap far stronger than found in previous G0W0 calculations but slightly overestimates its actual value due to the neglect of excitonic effects in W. A realistic frozen-lattice band gap of about 5.9 eV is obtained by combining hybrid density functional theory with the QSGW0 scheme. The renormalization of the band gap due to electron-phonon coupling, derived here using molecular dynamics as well as density functional perturbation theory, reduces this value by about 0.5 eV at room temperature. Spin-orbit coupling does not noticeably modify the fundamental gap but gives rise to a Rashba-like spin texture in the conduction band. article_number: '075205' article_type: original author: - first_name: Arthur full_name: Riefer, Arthur last_name: Riefer - first_name: Michael full_name: Friedrich, Michael last_name: Friedrich - first_name: Simone full_name: Sanna, Simone last_name: Sanna - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 citation: ama: 'Riefer A, Friedrich M, Sanna S, Gerstmann U, Schindlmayr A, Schmidt WG. LiNbO3 electronic structure: Many-body interactions, spin-orbit coupling, and thermal effects. Physical Review B. 2016;93(7). doi:10.1103/PhysRevB.93.075205' apa: 'Riefer, A., Friedrich, M., Sanna, S., Gerstmann, U., Schindlmayr, A., & Schmidt, W. G. (2016). LiNbO3 electronic structure: Many-body interactions, spin-orbit coupling, and thermal effects. Physical Review B, 93(7). https://doi.org/10.1103/PhysRevB.93.075205' bibtex: '@article{Riefer_Friedrich_Sanna_Gerstmann_Schindlmayr_Schmidt_2016, title={LiNbO3 electronic structure: Many-body interactions, spin-orbit coupling, and thermal effects}, volume={93}, DOI={10.1103/PhysRevB.93.075205}, number={7075205}, journal={Physical Review B}, publisher={American Physical Society}, author={Riefer, Arthur and Friedrich, Michael and Sanna, Simone and Gerstmann, Uwe and Schindlmayr, Arno and Schmidt, Wolf Gero}, year={2016} }' chicago: 'Riefer, Arthur, Michael Friedrich, Simone Sanna, Uwe Gerstmann, Arno Schindlmayr, and Wolf Gero Schmidt. “LiNbO3 Electronic Structure: Many-Body Interactions, Spin-Orbit Coupling, and Thermal Effects.” Physical Review B 93, no. 7 (2016). https://doi.org/10.1103/PhysRevB.93.075205.' ieee: 'A. Riefer, M. Friedrich, S. Sanna, U. Gerstmann, A. Schindlmayr, and W. G. Schmidt, “LiNbO3 electronic structure: Many-body interactions, spin-orbit coupling, and thermal effects,” Physical Review B, vol. 93, no. 7, 2016.' mla: 'Riefer, Arthur, et al. “LiNbO3 Electronic Structure: Many-Body Interactions, Spin-Orbit Coupling, and Thermal Effects.” Physical Review B, vol. 93, no. 7, 075205, American Physical Society, 2016, doi:10.1103/PhysRevB.93.075205.' short: A. Riefer, M. Friedrich, S. Sanna, U. Gerstmann, A. Schindlmayr, W.G. Schmidt, Physical Review B 93 (2016). date_created: 2019-05-29T07:50:59Z date_updated: 2022-01-06T06:50:26Z ddc: - '530' department: - _id: '295' - _id: '296' - _id: '230' - _id: '429' doi: 10.1103/PhysRevB.93.075205 external_id: isi: - '000370794800004' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-27T20:36:43Z date_updated: 2020-08-30T14:39:23Z description: © 2016 American Physical Society file_id: '18469' file_name: PhysRevB.93.075205.pdf file_size: 1314637 relation: main_file title: 'LiNbO3 electronic structure: Many-body interactions, spin-orbit coupling, and thermal effects' file_date_updated: 2020-08-30T14:39:23Z has_accepted_license: '1' intvolume: ' 93' isi: '1' issue: '7' language: - iso: eng oa: '1' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 publication: Physical Review B publication_identifier: eissn: - 2469-9969 issn: - 2469-9950 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: 'LiNbO3 electronic structure: Many-body interactions, spin-orbit coupling, and thermal effects' type: journal_article user_id: '458' volume: 93 year: '2016' ... --- _id: '10025' abstract: - lang: eng text: The phonon dispersions of the ferro‐ and paraelectric phase of LiTaO3 are calculated within density‐functional perturbation theory. The longitudinal optical phonon modes are theoretically derived and compared with available experimental data. Our results confirm the recent phonon assignment proposed by Margueron et al. [J. Appl. Phys. 111, 104105 (2012)] on the basis of spectroscopical studies. A comparison with the phonon band structure of the related material LiNbO3 shows minor differences that can be traced to the atomic‐mass difference between Ta and Nb. The presence of phonons with imaginary frequencies for the paraelectric phase suggests that it does not correspond to a minimum energy structure, and is compatible with an order‐disorder type phase transition. article_type: original author: - first_name: Michael full_name: Friedrich, Michael last_name: Friedrich - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Simone full_name: Sanna, Simone last_name: Sanna citation: ama: Friedrich M, Schindlmayr A, Schmidt WG, Sanna S. LiTaO3 phonon dispersion and ferroelectric transition calculated from first principles. Physica Status Solidi B. 2016;253(4):683-689. doi:10.1002/pssb.201552576 apa: Friedrich, M., Schindlmayr, A., Schmidt, W. G., & Sanna, S. (2016). LiTaO3 phonon dispersion and ferroelectric transition calculated from first principles. Physica Status Solidi B, 253(4), 683–689. https://doi.org/10.1002/pssb.201552576 bibtex: '@article{Friedrich_Schindlmayr_Schmidt_Sanna_2016, title={LiTaO3 phonon dispersion and ferroelectric transition calculated from first principles}, volume={253}, DOI={10.1002/pssb.201552576}, number={4}, journal={Physica Status Solidi B}, publisher={Wiley-VCH}, author={Friedrich, Michael and Schindlmayr, Arno and Schmidt, Wolf Gero and Sanna, Simone}, year={2016}, pages={683–689} }' chicago: 'Friedrich, Michael, Arno Schindlmayr, Wolf Gero Schmidt, and Simone Sanna. “LiTaO3 Phonon Dispersion and Ferroelectric Transition Calculated from First Principles.” Physica Status Solidi B 253, no. 4 (2016): 683–89. https://doi.org/10.1002/pssb.201552576.' ieee: M. Friedrich, A. Schindlmayr, W. G. Schmidt, and S. Sanna, “LiTaO3 phonon dispersion and ferroelectric transition calculated from first principles,” Physica Status Solidi B, vol. 253, no. 4, pp. 683–689, 2016. mla: Friedrich, Michael, et al. “LiTaO3 Phonon Dispersion and Ferroelectric Transition Calculated from First Principles.” Physica Status Solidi B, vol. 253, no. 4, Wiley-VCH, 2016, pp. 683–89, doi:10.1002/pssb.201552576. short: M. Friedrich, A. Schindlmayr, W.G. Schmidt, S. Sanna, Physica Status Solidi B 253 (2016) 683–689. date_created: 2019-05-29T07:52:52Z date_updated: 2022-01-06T06:50:26Z ddc: - '530' department: - _id: '295' - _id: '296' - _id: '230' - _id: '429' doi: 10.1002/pssb.201552576 external_id: isi: - '000374142500015' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T14:22:11Z date_updated: 2020-08-30T14:41:39Z description: © 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim file_id: '18577' file_name: pssb.201552576.pdf file_size: 402594 relation: main_file title: LiTaO3 phonon dispersion and ferroelectric transition calculated from first principles file_date_updated: 2020-08-30T14:41:39Z has_accepted_license: '1' intvolume: ' 253' isi: '1' issue: '4' language: - iso: eng page: 683-689 project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 publication: Physica Status Solidi B publication_identifier: eissn: - 1521-3951 issn: - 0370-1972 publication_status: published publisher: Wiley-VCH quality_controlled: '1' status: public title: LiTaO3 phonon dispersion and ferroelectric transition calculated from first principles type: journal_article user_id: '458' volume: 253 year: '2016' ... --- _id: '10030' abstract: - lang: eng text: The vibrational properties of stoichiometric LiNbO3 are analyzed within density-functional perturbation theory in order to obtain the complete phonon dispersion of the material. The phonon density of states of the ferroelectric (paraelectric) phase shows two (one) distinct band gaps separating the high-frequency (~800 cm−1) optical branches from the continuum of acoustic and lower optical phonon states. This result leads to specific heat capacites in close agreement with experimental measurements in the range 0–350 K and a Debye temperature of 574 K. The calculated zero-point renormalization of the electronic Kohn–Sham eigenvalues reveals a strong dependence on the phonon wave vectors, especially near Γ. Integrated over all phonon modes, our results indicate a vibrational correction of the electronic band gap of 0.41 eV at 0 K, which is in excellent agreement with the extrapolated temperature-dependent measurements. article_number: '385402' article_type: original author: - first_name: Michael full_name: Friedrich, Michael last_name: Friedrich - first_name: Arthur full_name: Riefer, Arthur last_name: Riefer - first_name: Simone full_name: Sanna, Simone last_name: Sanna - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Friedrich M, Riefer A, Sanna S, Schmidt WG, Schindlmayr A. Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory. Journal of Physics: Condensed Matter. 2015;27(38). doi:10.1088/0953-8984/27/38/385402' apa: 'Friedrich, M., Riefer, A., Sanna, S., Schmidt, W. G., & Schindlmayr, A. (2015). Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory. Journal of Physics: Condensed Matter, 27(38). https://doi.org/10.1088/0953-8984/27/38/385402' bibtex: '@article{Friedrich_Riefer_Sanna_Schmidt_Schindlmayr_2015, title={Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory}, volume={27}, DOI={10.1088/0953-8984/27/38/385402}, number={38385402}, journal={Journal of Physics: Condensed Matter}, publisher={IOP Publishing}, author={Friedrich, Michael and Riefer, Arthur and Sanna, Simone and Schmidt, Wolf Gero and Schindlmayr, Arno}, year={2015} }' chicago: 'Friedrich, Michael, Arthur Riefer, Simone Sanna, Wolf Gero Schmidt, and Arno Schindlmayr. “Phonon Dispersion and Zero-Point Renormalization of LiNbO3 from Density-Functional Perturbation Theory.” Journal of Physics: Condensed Matter 27, no. 38 (2015). https://doi.org/10.1088/0953-8984/27/38/385402.' ieee: 'M. Friedrich, A. Riefer, S. Sanna, W. G. Schmidt, and A. Schindlmayr, “Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory,” Journal of Physics: Condensed Matter, vol. 27, no. 38, 2015.' mla: 'Friedrich, Michael, et al. “Phonon Dispersion and Zero-Point Renormalization of LiNbO3 from Density-Functional Perturbation Theory.” Journal of Physics: Condensed Matter, vol. 27, no. 38, 385402, IOP Publishing, 2015, doi:10.1088/0953-8984/27/38/385402.' short: 'M. Friedrich, A. Riefer, S. Sanna, W.G. Schmidt, A. Schindlmayr, Journal of Physics: Condensed Matter 27 (2015).' date_created: 2019-05-29T08:41:18Z date_updated: 2022-01-06T06:50:27Z ddc: - '530' department: - _id: '295' - _id: '296' - _id: '230' - _id: '429' doi: 10.1088/0953-8984/27/38/385402 external_id: isi: - '000362549700004' pmid: - '26337951' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T14:24:23Z date_updated: 2020-08-30T14:46:56Z description: © 2015 IOP Publishing Ltd file_id: '18578' file_name: Friedrich_2015_J._Phys. _Condens._Matter_27_385402.pdf file_size: 1793430 relation: main_file title: Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory file_date_updated: 2020-08-30T14:46:56Z has_accepted_license: '1' intvolume: ' 27' isi: '1' issue: '38' language: - iso: eng pmid: '1' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 publication: 'Journal of Physics: Condensed Matter' publication_identifier: eissn: - 1361-648X issn: - 0953-8984 publication_status: published publisher: IOP Publishing quality_controlled: '1' status: public title: Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory type: journal_article user_id: '458' volume: 27 year: '2015' ... --- _id: '18470' abstract: - lang: eng text: Using ab initio computational methods, we study the structural and electronic properties of strained silicon, which has emerged as a promising technology to improve the performance of silicon-based metal-oxide-semiconductor field-effect transistors. In particular, higher electron mobilities are observed in n-doped samples with monoclinic strain along the [110] direction, and experimental evidence relates this to changes in the effective mass as well as the scattering rates. To assess the relative importance of these two factors, we combine density-functional theory in the local-density approximation with the GW approximation for the electronic self-energy and investigate the effect of uniaxial and biaxial strains along the [110] direction on the structural and electronic properties of Si. Longitudinal and transverse components of the electron effective mass as a function of the strain are derived from fits to the quasiparticle band structure and a diagonalization of the full effective-mass tensor. The changes in the effective masses and the energy splitting of the conduction-band valleys for uniaxial and biaxial strains as well as their impact on the electron mobility are analyzed. The self-energy corrections within GW lead to band gaps in excellent agreement with experimental measurements and slightly larger effective masses than in the local-density approximation. article_number: '453125' article_type: original author: - first_name: Mohammed full_name: Bouhassoune, Mohammed last_name: Bouhassoune - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Bouhassoune M, Schindlmayr A. Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon. Advances in Condensed Matter Physics. 2015;2015. doi:10.1155/2015/453125 apa: Bouhassoune, M., & Schindlmayr, A. (2015). Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon. Advances in Condensed Matter Physics, 2015, Article 453125. https://doi.org/10.1155/2015/453125 bibtex: '@article{Bouhassoune_Schindlmayr_2015, title={Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon}, volume={2015}, DOI={10.1155/2015/453125}, number={453125}, journal={Advances in Condensed Matter Physics}, publisher={Hindawi}, author={Bouhassoune, Mohammed and Schindlmayr, Arno}, year={2015} }' chicago: Bouhassoune, Mohammed, and Arno Schindlmayr. “Ab Initio Study of Strain Effects on the Quasiparticle Bands and Effective Masses in Silicon.” Advances in Condensed Matter Physics 2015 (2015). https://doi.org/10.1155/2015/453125. ieee: 'M. Bouhassoune and A. Schindlmayr, “Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon,” Advances in Condensed Matter Physics, vol. 2015, Art. no. 453125, 2015, doi: 10.1155/2015/453125.' mla: Bouhassoune, Mohammed, and Arno Schindlmayr. “Ab Initio Study of Strain Effects on the Quasiparticle Bands and Effective Masses in Silicon.” Advances in Condensed Matter Physics, vol. 2015, 453125, Hindawi, 2015, doi:10.1155/2015/453125. short: M. Bouhassoune, A. Schindlmayr, Advances in Condensed Matter Physics 2015 (2015). date_created: 2020-08-27T20:45:37Z date_updated: 2022-02-04T13:41:37Z ddc: - '530' department: - _id: '296' doi: 10.1155/2015/453125 external_id: isi: - '000350656500001' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T09:42:44Z date_updated: 2020-08-30T14:45:29Z description: Creative Commons Attribution 3.0 Unported Public License (CC BY 3.0) file_id: '18540' file_name: 453125.pdf file_size: 560248 relation: main_file title: Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon file_date_updated: 2020-08-30T14:45:29Z has_accepted_license: '1' intvolume: ' 2015' isi: '1' language: - iso: eng oa: '1' publication: Advances in Condensed Matter Physics publication_identifier: eissn: - 1687-8124 issn: - 1687-8108 publication_status: published publisher: Hindawi quality_controlled: '1' status: public title: Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon type: journal_article user_id: '458' volume: 2015 year: '2015' ... --- _id: '18471' abstract: - lang: eng text: Collective spin excitations form a fundamental class of excitations in magnetic materials. As their energy reaches down to only a few meV, they are present at all temperatures and substantially influence the properties of magnetic systems. To study the spin excitations in solids from first principles, we have developed a computational scheme based on many-body perturbation theory within the full-potential linearized augmented plane-wave (FLAPW) method. The main quantity of interest is the dynamical transverse spin susceptibility or magnetic response function, from which magnetic excitations, including single-particle spin-flip Stoner excitations and collective spin-wave modes as well as their lifetimes, can be obtained. In order to describe spin waves we include appropriate vertex corrections in the form of a multiple-scattering T matrix, which describes the coupling of electrons and holes with different spins. The electron–hole interaction incorporates the screening of the many-body system within the random-phase approximation. To reduce the numerical cost in evaluating the four-point T matrix, we exploit a transformation to maximally localized Wannier functions that takes advantage of the short spatial range of electronic correlation in the partially filled d or f orbitals of magnetic materials. The theory and the implementation are discussed in detail. In particular, we show how the magnetic response function can be evaluated for arbitrary k points. This enables the calculation of smooth dispersion curves, allowing one to study fine details in the k dependence of the spin-wave spectra. We also demonstrate how spatial and time-reversal symmetry can be exploited to accelerate substantially the computation of the four-point quantities. As an illustration, we present spin-wave spectra and dispersions for the elementary ferromagnet bcc Fe, B2-type tetragonal FeCo, and CrO2 calculated with our scheme. The results are in good agreement with available experimental data. author: - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Ersoy full_name: Şaşıoğlu, Ersoy last_name: Şaşıoğlu - first_name: Mathias full_name: Müller, Mathias last_name: Müller - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel citation: ama: 'Friedrich C, Şaşıoğlu E, Müller M, Schindlmayr A, Blügel S. Spin excitations in solids from many-body perturbation theory. In: Di Valentin C, Botti S, Cococcioni M, eds. First Principles Approaches to Spectroscopic Properties of Complex Materials. Vol 347. Topics in Current Chemistry. Berlin, Heidelberg: Springer; 2014:259-301. doi:10.1007/128_2013_518' apa: 'Friedrich, C., Şaşıoğlu, E., Müller, M., Schindlmayr, A., & Blügel, S. (2014). Spin excitations in solids from many-body perturbation theory. In C. Di Valentin, S. Botti, & M. Cococcioni (Eds.), First Principles Approaches to Spectroscopic Properties of Complex Materials (Vol. 347, pp. 259–301). Berlin, Heidelberg: Springer. https://doi.org/10.1007/128_2013_518' bibtex: '@inbook{Friedrich_Şaşıoğlu_Müller_Schindlmayr_Blügel_2014, place={Berlin, Heidelberg}, series={ Topics in Current Chemistry}, title={Spin excitations in solids from many-body perturbation theory}, volume={347}, DOI={10.1007/128_2013_518}, booktitle={First Principles Approaches to Spectroscopic Properties of Complex Materials}, publisher={Springer}, author={Friedrich, Christoph and Şaşıoğlu, Ersoy and Müller, Mathias and Schindlmayr, Arno and Blügel, Stefan}, editor={Di Valentin, Cristiana and Botti, Silvana and Cococcioni, MatteoEditors}, year={2014}, pages={259–301}, collection={ Topics in Current Chemistry} }' chicago: 'Friedrich, Christoph, Ersoy Şaşıoğlu, Mathias Müller, Arno Schindlmayr, and Stefan Blügel. “Spin Excitations in Solids from Many-Body Perturbation Theory.” In First Principles Approaches to Spectroscopic Properties of Complex Materials, edited by Cristiana Di Valentin, Silvana Botti, and Matteo Cococcioni, 347:259–301. Topics in Current Chemistry. Berlin, Heidelberg: Springer, 2014. https://doi.org/10.1007/128_2013_518.' ieee: 'C. Friedrich, E. Şaşıoğlu, M. Müller, A. Schindlmayr, and S. Blügel, “Spin excitations in solids from many-body perturbation theory,” in First Principles Approaches to Spectroscopic Properties of Complex Materials, vol. 347, C. Di Valentin, S. Botti, and M. Cococcioni, Eds. Berlin, Heidelberg: Springer, 2014, pp. 259–301.' mla: Friedrich, Christoph, et al. “Spin Excitations in Solids from Many-Body Perturbation Theory.” First Principles Approaches to Spectroscopic Properties of Complex Materials, edited by Cristiana Di Valentin et al., vol. 347, Springer, 2014, pp. 259–301, doi:10.1007/128_2013_518. short: 'C. Friedrich, E. Şaşıoğlu, M. Müller, A. Schindlmayr, S. Blügel, in: C. Di Valentin, S. Botti, M. Cococcioni (Eds.), First Principles Approaches to Spectroscopic Properties of Complex Materials, Springer, Berlin, Heidelberg, 2014, pp. 259–301.' date_created: 2020-08-27T21:00:45Z date_updated: 2022-01-06T06:53:34Z ddc: - '530' department: - _id: '296' doi: 10.1007/128_2013_518 editor: - first_name: Cristiana full_name: Di Valentin, Cristiana last_name: Di Valentin - first_name: Silvana full_name: Botti, Silvana last_name: Botti - first_name: Matteo full_name: Cococcioni, Matteo last_name: Cococcioni external_id: isi: - '000356811000008' pmid: - '24577607' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T15:19:57Z date_updated: 2020-08-30T14:48:45Z description: © 2014 Springer-Verlag, Berlin, Heidelberg file_id: '18584' file_name: Friedrich2014_Chapter_SpinExcitationsInSolidsFromMan.pdf file_size: 1061365 relation: main_file title: Spin excitations in solids from many-body perturbation theory file_date_updated: 2020-08-30T14:48:45Z has_accepted_license: '1' intvolume: ' 347' isi: '1' language: - iso: eng page: 259-301 place: Berlin, Heidelberg pmid: '1' publication: First Principles Approaches to Spectroscopic Properties of Complex Materials publication_identifier: eisbn: - 978-3-642-55068-3 eissn: - 1436-5049 isbn: - 978-3-642-55067-6 issn: - 0340-1022 publication_status: published publisher: Springer quality_controlled: '1' series_title: ' Topics in Current Chemistry' status: public title: Spin excitations in solids from many-body perturbation theory type: book_chapter user_id: '458' volume: 347 year: '2014' ... --- _id: '18472' abstract: - lang: eng text: Many-body perturbation theory is a well-established ab initio electronic-structure method based on Green functions. Although computationally more demanding than density functional theory, it has the distinct advantage that the exact expressions for all relevant observables, including the ground-state total energy, in terms of the Green function are known explicitly. The most important application, however, lies in the calculation of excited states, whose energies correspond directly to the poles of the Green function in the complex frequency plane. The accuracy of results obtained within this framework is only limited by the choice of the exchange-correlation self-energy, which must still be approximated in actual implementations. In this respect, the GW approximation has proved highly successful for systems governed by the Coulomb interaction. It yields band structures of solids, including the band gaps of semiconductors, as well as atomic and molecular ionization energies in very good quantitative agreement with experimental photoemission data. author: - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Schindlmayr A. The GW approximation for the electronic self-energy. In: Bach V, Delle Site L, eds. Many-Electron Approaches in Physics, Chemistry and Mathematics. Vol 29. Mathematical Physics Studies. Cham: Springer; 2014:343-357. doi:10.1007/978-3-319-06379-9_19' apa: 'Schindlmayr, A. (2014). The GW approximation for the electronic self-energy. In V. Bach & L. Delle Site (Eds.), Many-Electron Approaches in Physics, Chemistry and Mathematics (Vol. 29, pp. 343–357). Cham: Springer. https://doi.org/10.1007/978-3-319-06379-9_19' bibtex: '@inbook{Schindlmayr_2014, place={Cham}, series={ Mathematical Physics Studies}, title={The GW approximation for the electronic self-energy}, volume={29}, DOI={10.1007/978-3-319-06379-9_19}, booktitle={Many-Electron Approaches in Physics, Chemistry and Mathematics}, publisher={Springer}, author={Schindlmayr, Arno}, editor={Bach, Volker and Delle Site, LuigiEditors}, year={2014}, pages={343–357}, collection={ Mathematical Physics Studies} }' chicago: 'Schindlmayr, Arno. “The GW Approximation for the Electronic Self-Energy.” In Many-Electron Approaches in Physics, Chemistry and Mathematics, edited by Volker Bach and Luigi Delle Site, 29:343–57. Mathematical Physics Studies. Cham: Springer, 2014. https://doi.org/10.1007/978-3-319-06379-9_19.' ieee: 'A. Schindlmayr, “The GW approximation for the electronic self-energy,” in Many-Electron Approaches in Physics, Chemistry and Mathematics, vol. 29, V. Bach and L. Delle Site, Eds. Cham: Springer, 2014, pp. 343–357.' mla: Schindlmayr, Arno. “The GW Approximation for the Electronic Self-Energy.” Many-Electron Approaches in Physics, Chemistry and Mathematics, edited by Volker Bach and Luigi Delle Site, vol. 29, Springer, 2014, pp. 343–57, doi:10.1007/978-3-319-06379-9_19. short: 'A. Schindlmayr, in: V. Bach, L. Delle Site (Eds.), Many-Electron Approaches in Physics, Chemistry and Mathematics, Springer, Cham, 2014, pp. 343–357.' date_created: 2020-08-27T21:11:43Z date_updated: 2022-01-06T06:53:34Z ddc: - '530' department: - _id: '296' doi: 10.1007/978-3-319-06379-9_19 editor: - first_name: Volker full_name: Bach, Volker last_name: Bach - first_name: Luigi full_name: Delle Site, Luigi last_name: Delle Site file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T15:25:10Z date_updated: 2020-08-30T14:50:18Z description: © 2014 Springer International Publishing, Switzerland file_id: '18585' file_name: Schindlmayr2014_Chapter_TheGWApproximationForTheElectr.pdf file_size: 309579 relation: main_file title: The GW approximation for the electronic self-energy file_date_updated: 2020-08-30T14:50:18Z has_accepted_license: '1' intvolume: ' 29' language: - iso: eng page: 343-357 place: Cham publication: Many-Electron Approaches in Physics, Chemistry and Mathematics publication_identifier: eisbn: - 978-3-319-06379-9 eissn: - 2352-3905 isbn: - 978-3-319-06378-2 issn: - 0921-3767 publication_status: published publisher: Springer quality_controlled: '1' series_title: ' Mathematical Physics Studies' status: public title: The GW approximation for the electronic self-energy type: book_chapter user_id: '458' volume: 29 year: '2014' ... --- _id: '18473' abstract: - lang: eng text: We investigate the band dispersion and related electronic properties of picene single crystals within the GW approximation for the electronic self-energy. The width of the upper highest occupied molecular orbital (HOMOu) band along the Γ–Y direction, corresponding to the b crystal axis in real space along which the molecules are stacked, is determined to be 0.60 eV and thus 0.11 eV larger than the value obtained from density-functional theory. As in our recent study of rubrene using the same methodology [S. Yanagisawa, Y. Morikawa, and A. Schindlmayr, Phys. Rev. B 88, 115438 (2013)], this increase in the bandwidth is due to the strong variation of the GW self-energy correction across the Brillouin zone, which in turn reflects the increasing hybridization of the HOMOu states of neighboring picene molecules from Γ to Y. In contrast, the width of the lower HOMO (HOMOl) band along Γ–Y remains almost unchanged, consistent with the fact that the HOMOl(Γ) and HOMOl(Y) states exhibit the same degree of hybridization, so that the nodal structure of the wave functions and the matrix elements of the self-energy correction are very similar. article_number: 05FY02 article_type: original author: - first_name: Susumu full_name: Yanagisawa, Susumu last_name: Yanagisawa - first_name: Yoshitada full_name: Morikawa, Yoshitada last_name: Morikawa - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Yanagisawa S, Morikawa Y, Schindlmayr A. Theoretical investigation of the band structure of picene single crystals within the GW approximation. Japanese Journal of Applied Physics. 2014;53(5S1). doi:10.7567/jjap.53.05fy02 apa: Yanagisawa, S., Morikawa, Y., & Schindlmayr, A. (2014). Theoretical investigation of the band structure of picene single crystals within the GW approximation. Japanese Journal of Applied Physics, 53(5S1). https://doi.org/10.7567/jjap.53.05fy02 bibtex: '@article{Yanagisawa_Morikawa_Schindlmayr_2014, title={Theoretical investigation of the band structure of picene single crystals within the GW approximation}, volume={53}, DOI={10.7567/jjap.53.05fy02}, number={5S105FY02}, journal={Japanese Journal of Applied Physics}, publisher={IOP Publishing and The Japan Society of Applied Physics}, author={Yanagisawa, Susumu and Morikawa, Yoshitada and Schindlmayr, Arno}, year={2014} }' chicago: Yanagisawa, Susumu, Yoshitada Morikawa, and Arno Schindlmayr. “Theoretical Investigation of the Band Structure of Picene Single Crystals within the GW Approximation.” Japanese Journal of Applied Physics 53, no. 5S1 (2014). https://doi.org/10.7567/jjap.53.05fy02. ieee: S. Yanagisawa, Y. Morikawa, and A. Schindlmayr, “Theoretical investigation of the band structure of picene single crystals within the GW approximation,” Japanese Journal of Applied Physics, vol. 53, no. 5S1, 2014. mla: Yanagisawa, Susumu, et al. “Theoretical Investigation of the Band Structure of Picene Single Crystals within the GW Approximation.” Japanese Journal of Applied Physics, vol. 53, no. 5S1, 05FY02, IOP Publishing and The Japan Society of Applied Physics, 2014, doi:10.7567/jjap.53.05fy02. short: S. Yanagisawa, Y. Morikawa, A. Schindlmayr, Japanese Journal of Applied Physics 53 (2014). date_created: 2020-08-27T21:21:24Z date_updated: 2022-01-06T06:53:34Z ddc: - '530' department: - _id: '296' doi: 10.7567/jjap.53.05fy02 external_id: isi: - '000338316200158' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T14:28:20Z date_updated: 2020-08-30T14:52:27Z description: © 2014 The Japan Society of Applied Physics file_id: '18579' file_name: Yanagisawa_2014_Jpn._J._Appl._Phys._53_05FY02.pdf file_size: 588607 relation: main_file title: Theoretical investigation of the band structure of picene single crystals within the GW approximation file_date_updated: 2020-08-30T14:52:27Z has_accepted_license: '1' intvolume: ' 53' isi: '1' issue: 5S1 language: - iso: eng publication: Japanese Journal of Applied Physics publication_identifier: eissn: - 1347-4065 issn: - 0021-4922 publication_status: published publisher: IOP Publishing and The Japan Society of Applied Physics quality_controlled: '1' status: public title: Theoretical investigation of the band structure of picene single crystals within the GW approximation type: journal_article user_id: '458' volume: 53 year: '2014' ... --- _id: '18474' author: - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Friedrich C, Schindlmayr A. Many-body perturbation theory: The GW approximation. In: Blügel S, Helbig N, Meden V, Wortmann D, eds. Computing Solids: Models, Ab Initio Methods and Supercomputing. Vol 74. Key Technologies. Jülich: Forschungszentrum Jülich; 2014:A4.1-A4.21.' apa: 'Friedrich, C., & Schindlmayr, A. (2014). Many-body perturbation theory: The GW approximation. In S. Blügel, N. Helbig, V. Meden, & D. Wortmann (Eds.), Computing Solids: Models, ab initio Methods and Supercomputing (Vol. 74, p. A4.1-A4.21). Jülich: Forschungszentrum Jülich.' bibtex: '@inbook{Friedrich_Schindlmayr_2014, place={Jülich}, series={Key Technologies}, title={Many-body perturbation theory: The GW approximation}, volume={74}, booktitle={Computing Solids: Models, ab initio Methods and Supercomputing}, publisher={Forschungszentrum Jülich}, author={Friedrich, Christoph and Schindlmayr, Arno}, editor={Blügel, Stefan and Helbig, Nicole and Meden, Volker and Wortmann, DanielEditors}, year={2014}, pages={A4.1-A4.21}, collection={Key Technologies} }' chicago: 'Friedrich, Christoph, and Arno Schindlmayr. “Many-Body Perturbation Theory: The GW Approximation.” In Computing Solids: Models, Ab Initio Methods and Supercomputing, edited by Stefan Blügel, Nicole Helbig, Volker Meden, and Daniel Wortmann, 74:A4.1-A4.21. Key Technologies. Jülich: Forschungszentrum Jülich, 2014.' ieee: 'C. Friedrich and A. Schindlmayr, “Many-body perturbation theory: The GW approximation,” in Computing Solids: Models, ab initio Methods and Supercomputing, vol. 74, S. Blügel, N. Helbig, V. Meden, and D. Wortmann, Eds. Jülich: Forschungszentrum Jülich, 2014, p. A4.1-A4.21.' mla: 'Friedrich, Christoph, and Arno Schindlmayr. “Many-Body Perturbation Theory: The GW Approximation.” Computing Solids: Models, Ab Initio Methods and Supercomputing, edited by Stefan Blügel et al., vol. 74, Forschungszentrum Jülich, 2014, p. A4.1-A4.21.' short: 'C. Friedrich, A. Schindlmayr, in: S. Blügel, N. Helbig, V. Meden, D. Wortmann (Eds.), Computing Solids: Models, Ab Initio Methods and Supercomputing, Forschungszentrum Jülich, Jülich, 2014, p. A4.1-A4.21.' conference: end_date: 2014-03-21 location: Jülich name: 45th Spring School of the Institute of Solid State Research start_date: 2014-03-10 date_created: 2020-08-27T21:40:39Z date_updated: 2022-01-06T06:53:35Z ddc: - '530' department: - _id: '296' editor: - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel - first_name: Nicole full_name: Helbig, Nicole last_name: Helbig - first_name: Volker full_name: Meden, Volker last_name: Meden - first_name: Daniel full_name: Wortmann, Daniel last_name: Wortmann file: - access_level: request content_type: application/pdf creator: schindlm date_created: 2020-10-05T10:57:49Z date_updated: 2022-01-06T06:53:34Z description: © 2014 Forschungszentrum Jülich file_id: '19876' file_name: A4-Friedrich.pdf file_size: 718521 relation: main_file title: 'Many-body perturbation theory: The GW approximation' file_date_updated: 2022-01-06T06:53:34Z has_accepted_license: '1' intvolume: ' 74' language: - iso: eng main_file_link: - open_access: '1' url: http://hdl.handle.net/2128/8540 oa: '1' page: A4.1-A4.21 place: Jülich publication: 'Computing Solids: Models, ab initio Methods and Supercomputing' publication_identifier: isbn: - 978-3-89336-912-6 issn: - 1866-1807 publication_status: published publisher: Forschungszentrum Jülich series_title: Key Technologies status: public title: 'Many-body perturbation theory: The GW approximation' type: book_chapter user_id: '458' volume: 74 year: '2014' ... --- _id: '18475' abstract: - lang: eng text: The frequency-dependent dielectric function and the second-order polarizability tensor of ferroelectric LiNbO3 are calculated from first principles. The calculations are based on the electronic structure obtained from density-functional theory. The subsequent application of the GW approximation to account for quasiparticle effects and the solution of the Bethe–Salpeter equation yield a dielectric function for the stoichiometric material that slightly overestimates the absorption onset and the oscillator strength in comparison with experimental measurements. Calculations at the level of the independent-particle approximation indicate that these deficiencies are at least partially related to the neglect of intrinsic defects typical for the congruent material. The second-order polarizability calculated within the independent-particle approximation predicts strong nonlinear coefficients for photon energies above 1.5 eV. The comparison with measured data suggests that self-energy effects improve the agreement between experiment and theory. The intrinsic defects of congruent samples reduce the optical nonlinearities, in particular for the 21 and 31 tensor components, further improving the agreement with measured data. author: - first_name: Arthur full_name: Riefer, Arthur last_name: Riefer - first_name: Martin full_name: Rohrmüller, Martin last_name: Rohrmüller - first_name: Marc full_name: Landmann, Marc last_name: Landmann - first_name: Simone full_name: Sanna, Simone last_name: Sanna - first_name: Eva full_name: Rauls, Eva last_name: Rauls - first_name: Nora Jenny full_name: Vollmers, Nora Jenny last_name: Vollmers - first_name: Rebecca full_name: Hölscher, Rebecca last_name: Hölscher - first_name: Matthias full_name: Witte, Matthias last_name: Witte - first_name: Yanlu full_name: Li, Yanlu last_name: Li - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 citation: ama: 'Riefer A, Rohrmüller M, Landmann M, et al. Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations. In: Nagel WE, Kröner DH, Resch MM, eds. High Performance Computing in Science and Engineering ‘13. Transactions of the High Performance Computing Center, Stuttgart. Cham: Springer; 2013:93-104. doi:10.1007/978-3-319-02165-2_8' apa: 'Riefer, A., Rohrmüller, M., Landmann, M., Sanna, S., Rauls, E., Vollmers, N. J., … Schmidt, W. G. (2013). Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations. In W. E. Nagel, D. H. Kröner, & M. M. Resch (Eds.), High Performance Computing in Science and Engineering ‘13 (pp. 93–104). Cham: Springer. https://doi.org/10.1007/978-3-319-02165-2_8' bibtex: '@inbook{Riefer_Rohrmüller_Landmann_Sanna_Rauls_Vollmers_Hölscher_Witte_Li_Gerstmann_et al._2013, place={Cham}, series={Transactions of the High Performance Computing Center, Stuttgart}, title={Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations}, DOI={10.1007/978-3-319-02165-2_8}, booktitle={High Performance Computing in Science and Engineering ‘13}, publisher={Springer}, author={Riefer, Arthur and Rohrmüller, Martin and Landmann, Marc and Sanna, Simone and Rauls, Eva and Vollmers, Nora Jenny and Hölscher, Rebecca and Witte, Matthias and Li, Yanlu and Gerstmann, Uwe and et al.}, editor={Nagel, Wolfgang E. and Kröner, Dietmar H. and Resch, Michael M.Editors}, year={2013}, pages={93–104}, collection={Transactions of the High Performance Computing Center, Stuttgart} }' chicago: 'Riefer, Arthur, Martin Rohrmüller, Marc Landmann, Simone Sanna, Eva Rauls, Nora Jenny Vollmers, Rebecca Hölscher, et al. “Lithium Niobate Dielectric Function and Second-Order Polarizability Tensor from Massively Parallel Ab Initio Calculations.” In High Performance Computing in Science and Engineering ‘13, edited by Wolfgang E. Nagel, Dietmar H. Kröner, and Michael M. Resch, 93–104. Transactions of the High Performance Computing Center, Stuttgart. Cham: Springer, 2013. https://doi.org/10.1007/978-3-319-02165-2_8.' ieee: 'A. Riefer et al., “Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations,” in High Performance Computing in Science and Engineering ‘13, W. E. Nagel, D. H. Kröner, and M. M. Resch, Eds. Cham: Springer, 2013, pp. 93–104.' mla: Riefer, Arthur, et al. “Lithium Niobate Dielectric Function and Second-Order Polarizability Tensor from Massively Parallel Ab Initio Calculations.” High Performance Computing in Science and Engineering ‘13, edited by Wolfgang E. Nagel et al., Springer, 2013, pp. 93–104, doi:10.1007/978-3-319-02165-2_8. short: 'A. Riefer, M. Rohrmüller, M. Landmann, S. Sanna, E. Rauls, N.J. Vollmers, R. Hölscher, M. Witte, Y. Li, U. Gerstmann, A. Schindlmayr, W.G. Schmidt, in: W.E. Nagel, D.H. Kröner, M.M. Resch (Eds.), High Performance Computing in Science and Engineering ‘13, Springer, Cham, 2013, pp. 93–104.' date_created: 2020-08-27T21:48:43Z date_updated: 2022-01-06T06:53:35Z ddc: - '530' department: - _id: '296' - _id: '295' doi: 10.1007/978-3-319-02165-2_8 editor: - first_name: Wolfgang E. full_name: Nagel, Wolfgang E. last_name: Nagel - first_name: Dietmar H. full_name: Kröner, Dietmar H. last_name: Kröner - first_name: Michael M. full_name: Resch, Michael M. last_name: Resch external_id: isi: - '000360004100009' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T15:34:44Z date_updated: 2020-08-30T14:57:36Z description: © 2013 Springer International Publishing, Switzerland file_id: '18586' file_name: Riefer2013_Chapter_LithiumNiobateDielectricFuncti.pdf file_size: 517819 relation: main_file title: Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations file_date_updated: 2020-08-30T14:57:36Z has_accepted_license: '1' isi: '1' language: - iso: eng page: 93-104 place: Cham project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing publication: High Performance Computing in Science and Engineering ‘13 publication_identifier: eisbn: - 978-3-319-02165-2 isbn: - 978-3-319-02164-5 publication_status: published publisher: Springer quality_controlled: '1' series_title: Transactions of the High Performance Computing Center, Stuttgart status: public title: Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations type: book_chapter user_id: '458' year: '2013' ... --- _id: '18476' abstract: - lang: eng text: We investigate the band dispersion and relevant electronic properties of rubrene single crystals within the GW approximation. Due to the self-energy correction, the dispersion of the highest occupied molecular orbital (HOMO) band increases by 0.10 eV compared to the dispersion of the Kohn-Sham eigenvalues within the generalized gradient approximation, and the effective hole mass consequently decreases. The resulting value of 0.90 times the electron rest mass along the Γ-Y direction in the Brillouin zone is closer to experimental measurements than that obtained from density-functional theory. The enhanced bandwidth is explained in terms of the intermolecular hybridization of the HOMO(Y) wave function along the stacking direction of the molecules. Overall, our results support the bandlike interpretation of charge-carrier transport in rubrene. article_number: '115438' article_type: original author: - first_name: Susumu full_name: Yanagisawa, Susumu last_name: Yanagisawa - first_name: Yoshitada full_name: Morikawa, Yoshitada last_name: Morikawa - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Yanagisawa S, Morikawa Y, Schindlmayr A. HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation. Physical Review B. 2013;88(11). doi:10.1103/PhysRevB.88.115438' apa: 'Yanagisawa, S., Morikawa, Y., & Schindlmayr, A. (2013). HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation. Physical Review B, 88(11). https://doi.org/10.1103/PhysRevB.88.115438' bibtex: '@article{Yanagisawa_Morikawa_Schindlmayr_2013, title={HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation}, volume={88}, DOI={10.1103/PhysRevB.88.115438}, number={11115438}, journal={Physical Review B}, publisher={American Physical Society}, author={Yanagisawa, Susumu and Morikawa, Yoshitada and Schindlmayr, Arno}, year={2013} }' chicago: 'Yanagisawa, Susumu, Yoshitada Morikawa, and Arno Schindlmayr. “HOMO Band Dispersion of Crystalline Rubrene: Effects of Self-Energy Corrections within the GW Approximation.” Physical Review B 88, no. 11 (2013). https://doi.org/10.1103/PhysRevB.88.115438.' ieee: 'S. Yanagisawa, Y. Morikawa, and A. Schindlmayr, “HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation,” Physical Review B, vol. 88, no. 11, 2013.' mla: 'Yanagisawa, Susumu, et al. “HOMO Band Dispersion of Crystalline Rubrene: Effects of Self-Energy Corrections within the GW Approximation.” Physical Review B, vol. 88, no. 11, 115438, American Physical Society, 2013, doi:10.1103/PhysRevB.88.115438.' short: S. Yanagisawa, Y. Morikawa, A. Schindlmayr, Physical Review B 88 (2013). date_created: 2020-08-27T21:59:44Z date_updated: 2022-01-06T06:53:36Z ddc: - '530' department: - _id: '296' doi: 10.1103/PhysRevB.88.115438 external_id: isi: - '000325175600010' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-27T22:01:50Z date_updated: 2020-08-30T14:58:43Z description: © 2013 American Physical Society file_id: '18477' file_name: PhysRevB.88.115438.pdf file_size: 4438475 relation: main_file title: 'HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation' file_date_updated: 2020-08-30T14:58:43Z has_accepted_license: '1' intvolume: ' 88' isi: '1' issue: '11' language: - iso: eng oa: '1' publication: Physical Review B publication_identifier: eissn: - 1550-235X issn: - 1098-0121 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: 'HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation' type: journal_article user_id: '458' volume: 88 year: '2013' ... --- _id: '13525' abstract: - lang: eng text: The frequency-dependent dielectric function and the second-order polarizability tensor of ferroelectric LiNbO3 are calculated from first principles. The calculations are based on the electronic structure obtained from density-functional theory. The subsequent application of the GW approximation to account for quasiparticle effects and the solution of the Bethe-Salpeter equation for the stoichiometric material yield a dielectric function that slightly overestimates the absorption onset and the oscillator strength in comparison with experimental measurements. Calculations at the level of the independent-particle approximation indicate that these deficiencies are, at least, partially related to the neglect of intrinsic defects typical for the congruent material. The second-order polarizability calculated within the independent-particle approximation predicts strong nonlinear coefficients for photon energies above 1.5 eV. The comparison with measured data suggests that the inclusion of self-energy effects in the nonlinear optical response leads to a better agreement with experiments. The intrinsic defects of congruent samples reduce the optical nonlinearities, in particular, for the 21 and 31 tensor components, further improving the agreement between experiments and theory. article_number: '195208' article_type: original author: - first_name: Arthur full_name: Riefer, Arthur last_name: Riefer - first_name: Simone full_name: Sanna, Simone last_name: Sanna - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 citation: ama: Riefer A, Sanna S, Schindlmayr A, Schmidt WG. Optical response of stoichiometric and congruent lithium niobate from first-principles calculations. Physical Review B. 2013;87(19). doi:10.1103/PhysRevB.87.195208 apa: Riefer, A., Sanna, S., Schindlmayr, A., & Schmidt, W. G. (2013). Optical response of stoichiometric and congruent lithium niobate from first-principles calculations. Physical Review B, 87(19). https://doi.org/10.1103/PhysRevB.87.195208 bibtex: '@article{Riefer_Sanna_Schindlmayr_Schmidt_2013, title={Optical response of stoichiometric and congruent lithium niobate from first-principles calculations}, volume={87}, DOI={10.1103/PhysRevB.87.195208}, number={19195208}, journal={Physical Review B}, publisher={American Physical Society}, author={Riefer, Arthur and Sanna, Simone and Schindlmayr, Arno and Schmidt, Wolf Gero}, year={2013} }' chicago: Riefer, Arthur, Simone Sanna, Arno Schindlmayr, and Wolf Gero Schmidt. “Optical Response of Stoichiometric and Congruent Lithium Niobate from First-Principles Calculations.” Physical Review B 87, no. 19 (2013). https://doi.org/10.1103/PhysRevB.87.195208. ieee: A. Riefer, S. Sanna, A. Schindlmayr, and W. G. Schmidt, “Optical response of stoichiometric and congruent lithium niobate from first-principles calculations,” Physical Review B, vol. 87, no. 19, 2013. mla: Riefer, Arthur, et al. “Optical Response of Stoichiometric and Congruent Lithium Niobate from First-Principles Calculations.” Physical Review B, vol. 87, no. 19, 195208, American Physical Society, 2013, doi:10.1103/PhysRevB.87.195208. short: A. Riefer, S. Sanna, A. Schindlmayr, W.G. Schmidt, Physical Review B 87 (2013). date_created: 2019-09-30T14:11:18Z date_updated: 2022-01-06T06:51:38Z ddc: - '530' department: - _id: '295' - _id: '296' doi: 10.1103/PhysRevB.87.195208 external_id: isi: - '000319391000002' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-27T22:06:46Z date_updated: 2020-08-30T14:53:40Z description: © 2013 American Physical Society file_id: '18478' file_name: PhysRevB.87.195208.pdf file_size: 791961 relation: main_file title: Optical response of stoichiometric and congruent lithium niobate from first-principles calculations file_date_updated: 2020-08-30T14:53:40Z has_accepted_license: '1' intvolume: ' 87' isi: '1' issue: '19' language: - iso: eng oa: '1' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing publication: Physical Review B publication_identifier: eissn: - 1550-235X issn: - 1098-0121 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: Optical response of stoichiometric and congruent lithium niobate from first-principles calculations type: journal_article user_id: '458' volume: 87 year: '2013' ... --- _id: '18479' abstract: - lang: eng text: The GW approximation for the electronic self-energy is an important tool for the quantitative prediction of excited states in solids, but its mathematical exploration is hampered by the fact that it must, in general, be evaluated numerically even for very simple systems. In this paper I describe a nontrivial model consisting of two electrons on the surface of a sphere, interacting with the normal long-range Coulomb potential, and show that the GW self-energy, in the absence of self-consistency, can in fact be derived completely analytically in this case. The resulting expression is subsequently used to analyze the convergence of the energy gap between the highest occupied and the lowest unoccupied quasiparticle orbital with respect to the total number of states included in the spectral summations. The asymptotic formula for the truncation error obtained in this way, whose dominant contribution is proportional to the cutoff energy to the power −3/2, may be adapted to extrapolate energy gaps in other systems. article_number: '075104' article_type: original author: - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Schindlmayr A. Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere. Physical Review B. 2013;87(7). doi:10.1103/PhysRevB.87.075104 apa: Schindlmayr, A. (2013). Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere. Physical Review B, 87(7), Article 075104. https://doi.org/10.1103/PhysRevB.87.075104 bibtex: '@article{Schindlmayr_2013, title={Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere}, volume={87}, DOI={10.1103/PhysRevB.87.075104}, number={7075104}, journal={Physical Review B}, publisher={American Physical Society}, author={Schindlmayr, Arno}, year={2013} }' chicago: Schindlmayr, Arno. “Analytic Evaluation of the Electronic Self-Energy in the GW Approximation for Two Electrons on a Sphere.” Physical Review B 87, no. 7 (2013). https://doi.org/10.1103/PhysRevB.87.075104. ieee: 'A. Schindlmayr, “Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere,” Physical Review B, vol. 87, no. 7, Art. no. 075104, 2013, doi: 10.1103/PhysRevB.87.075104.' mla: Schindlmayr, Arno. “Analytic Evaluation of the Electronic Self-Energy in the GW Approximation for Two Electrons on a Sphere.” Physical Review B, vol. 87, no. 7, 075104, American Physical Society, 2013, doi:10.1103/PhysRevB.87.075104. short: A. Schindlmayr, Physical Review B 87 (2013). date_created: 2020-08-27T22:09:04Z date_updated: 2022-11-11T06:41:32Z ddc: - '530' department: - _id: '296' doi: 10.1103/PhysRevB.87.075104 external_id: arxiv: - '1302.6368' isi: - '000314682500002' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T10:01:56Z date_updated: 2020-08-30T14:54:49Z description: © 2013 American Physical Society file_id: '18541' file_name: PhysRevB.87.075104.pdf file_size: 229196 relation: main_file title: Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere file_date_updated: 2020-08-30T14:54:49Z has_accepted_license: '1' intvolume: ' 87' isi: '1' issue: '7' language: - iso: eng oa: '1' publication: Physical Review B publication_identifier: eissn: - 1550-235X issn: - 1098-0121 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere type: journal_article user_id: '458' volume: 87 year: '2013' ... --- _id: '18542' abstract: - lang: eng text: 'We present recent advances in numerical implementations of hybrid functionals and the GW approximation within the full-potential linearized augmented-plane-wave (FLAPW) method. The former is an approximation for the exchange–correlation contribution to the total energy functional in density-functional theory, and the latter is an approximation for the electronic self-energy in the framework of many-body perturbation theory. All implementations employ the mixed product basis, which has evolved into a versatile basis for the products of wave functions, describing the incoming and outgoing states of an electron that is scattered by interacting with another electron. It can thus be used for representing the nonlocal potential in hybrid functionals as well as the screened interaction and related quantities in GW calculations. In particular, the six-dimensional space integrals of the Hamiltonian exchange matrix elements (and exchange self-energy) decompose into sums over vector–matrix–vector products, which can be evaluated easily. The correlation part of the GW self-energy, which contains a time or frequency dependence, is calculated on the imaginary frequency axis with a subsequent analytic continuation to the real axis or, alternatively, by a direct frequency convolution of the Green function G and the dynamically screened Coulomb interaction W along a contour integration path that avoids the poles of the Green function. Hybrid-functional and GW calculations are notoriously computationally expensive. We present a number of tricks that reduce the computational cost considerably, including the use of spatial and time-reversal symmetries, modifications of the mixed product basis with the aim to optimize it for the correlation self-energy and another modification that makes the Coulomb matrix sparse, analytic expansions of the interaction potentials around the point of divergence at k=0, and a nested density and density-matrix convergence scheme for hybrid-functional calculations. We show CPU timings for prototype semiconductors and illustrative results for GdN and ZnO. ' article_number: '293201' article_type: review author: - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Markus full_name: Betzinger, Markus last_name: Betzinger - first_name: Martin full_name: Schlipf, Martin last_name: Schlipf - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Friedrich C, Betzinger M, Schlipf M, Blügel S, Schindlmayr A. Hybrid functionals and GW approximation in the FLAPW method. Journal of Physics: Condensed Matter. 2012;24(29). doi:10.1088/0953-8984/24/29/293201' apa: 'Friedrich, C., Betzinger, M., Schlipf, M., Blügel, S., & Schindlmayr, A. (2012). Hybrid functionals and GW approximation in the FLAPW method. Journal of Physics: Condensed Matter, 24(29). https://doi.org/10.1088/0953-8984/24/29/293201' bibtex: '@article{Friedrich_Betzinger_Schlipf_Blügel_Schindlmayr_2012, title={Hybrid functionals and GW approximation in the FLAPW method}, volume={24}, DOI={10.1088/0953-8984/24/29/293201}, number={29293201}, journal={Journal of Physics: Condensed Matter}, publisher={IOP Publishing}, author={Friedrich, Christoph and Betzinger, Markus and Schlipf, Martin and Blügel, Stefan and Schindlmayr, Arno}, year={2012} }' chicago: 'Friedrich, Christoph, Markus Betzinger, Martin Schlipf, Stefan Blügel, and Arno Schindlmayr. “Hybrid Functionals and GW Approximation in the FLAPW Method.” Journal of Physics: Condensed Matter 24, no. 29 (2012). https://doi.org/10.1088/0953-8984/24/29/293201.' ieee: 'C. Friedrich, M. Betzinger, M. Schlipf, S. Blügel, and A. Schindlmayr, “Hybrid functionals and GW approximation in the FLAPW method,” Journal of Physics: Condensed Matter, vol. 24, no. 29, 2012.' mla: 'Friedrich, Christoph, et al. “Hybrid Functionals and GW Approximation in the FLAPW Method.” Journal of Physics: Condensed Matter, vol. 24, no. 29, 293201, IOP Publishing, 2012, doi:10.1088/0953-8984/24/29/293201.' short: 'C. Friedrich, M. Betzinger, M. Schlipf, S. Blügel, A. Schindlmayr, Journal of Physics: Condensed Matter 24 (2012).' date_created: 2020-08-28T10:14:44Z date_updated: 2022-01-06T06:53:37Z ddc: - '530' department: - _id: '296' doi: 10.1088/0953-8984/24/29/293201 external_id: isi: - '000306270700001' pmid: - '22773268' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T14:30:29Z date_updated: 2020-08-30T15:00:14Z description: © 2012 IOP Publishing Ltd file_id: '18580' file_name: Friedrich_2012_J._Phys. _Condens._Matter_24_293201.pdf file_size: 1059896 relation: main_file title: Hybrid functionals and GW approximation in the FLAPW method file_date_updated: 2020-08-30T15:00:14Z has_accepted_license: '1' intvolume: ' 24' isi: '1' issue: '29' language: - iso: eng pmid: '1' publication: 'Journal of Physics: Condensed Matter' publication_identifier: eissn: - 1361-648X issn: - 0953-8984 publication_status: published publisher: IOP Publishing quality_controlled: '1' status: public title: Hybrid functionals and GW approximation in the FLAPW method type: journal_article user_id: '458' volume: 24 year: '2012' ... --- _id: '4091' abstract: - lang: eng text: 'We present a nonequilibrium ab initio method for calculating nonlinear and nonlocal optical effects in metallic slabs with a thickness of several nanometers. The numerical analysis is based on the full solution of the time‐dependent Kohn–Sham equations for a jellium system and allows to study the optical response of metal electrons subject to arbitrarily shaped intense light pulses. We find a strong localization of the generated second‐harmonic current in the surface regions of the slabs. ' article_type: original author: - first_name: Mathias full_name: Wand, Mathias last_name: Wand - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Torsten full_name: Meier, Torsten id: '344' last_name: Meier orcid: 0000-0001-8864-2072 - first_name: Jens full_name: Förstner, Jens id: '158' last_name: Förstner orcid: 0000-0001-7059-9862 citation: ama: Wand M, Schindlmayr A, Meier T, Förstner J. Simulation of the ultrafast nonlinear optical response of metal slabs. Physica Status Solidi B. 2011;248(4):887-891. doi:10.1002/pssb.201001219 apa: Wand, M., Schindlmayr, A., Meier, T., & Förstner, J. (2011). Simulation of the ultrafast nonlinear optical response of metal slabs. Physica Status Solidi B, 248(4), 887–891. https://doi.org/10.1002/pssb.201001219 bibtex: '@article{Wand_Schindlmayr_Meier_Förstner_2011, title={Simulation of the ultrafast nonlinear optical response of metal slabs}, volume={248}, DOI={10.1002/pssb.201001219}, number={4}, journal={Physica Status Solidi B}, publisher={Wiley-VCH}, author={Wand, Mathias and Schindlmayr, Arno and Meier, Torsten and Förstner, Jens}, year={2011}, pages={887–891} }' chicago: 'Wand, Mathias, Arno Schindlmayr, Torsten Meier, and Jens Förstner. “Simulation of the Ultrafast Nonlinear Optical Response of Metal Slabs.” Physica Status Solidi B 248, no. 4 (2011): 887–91. https://doi.org/10.1002/pssb.201001219.' ieee: 'M. Wand, A. Schindlmayr, T. Meier, and J. Förstner, “Simulation of the ultrafast nonlinear optical response of metal slabs,” Physica Status Solidi B, vol. 248, no. 4, pp. 887–891, 2011, doi: 10.1002/pssb.201001219.' mla: Wand, Mathias, et al. “Simulation of the Ultrafast Nonlinear Optical Response of Metal Slabs.” Physica Status Solidi B, vol. 248, no. 4, Wiley-VCH, 2011, pp. 887–91, doi:10.1002/pssb.201001219. short: M. Wand, A. Schindlmayr, T. Meier, J. Förstner, Physica Status Solidi B 248 (2011) 887–891. date_created: 2018-08-23T09:53:38Z date_updated: 2023-01-27T13:08:08Z ddc: - '530' department: - _id: '293' - _id: '230' - _id: '296' - _id: '15' - _id: '170' doi: 10.1002/pssb.201001219 external_id: isi: - '000288856300020' file: - access_level: closed content_type: application/pdf creator: hclaudia date_created: 2018-08-23T09:55:13Z date_updated: 2020-08-30T15:01:30Z description: © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim file_id: '4092' file_name: 2011 Wand,Schindlmayr,Meier,Förstner_Simulation of the ultrafast nonlinear optical response of metal slabs.pdf file_size: 739579 relation: main_file title: Simulation of the ultrafast optical response of metal slabs file_date_updated: 2020-08-30T15:01:30Z has_accepted_license: '1' intvolume: ' 248' isi: '1' issue: '4' keyword: - tet_topic_shg language: - iso: eng page: 887-891 publication: Physica Status Solidi B publication_identifier: eissn: - 1521-3951 issn: - 0370-1972 publication_status: published publisher: Wiley-VCH quality_controlled: '1' status: public title: Simulation of the ultrafast nonlinear optical response of metal slabs type: journal_article user_id: '16199' volume: 248 year: '2011' ... --- _id: '4048' abstract: - lang: eng text: We present an ab-initio method for calculating nonlinear and nonlocal optical effects in metallic slabs with sub-wavelength thickness. We find a strong localization of the second-harmonic current at the metal-vacuum interface. article_number: JTuI59 author: - first_name: Mathias full_name: Wand, Mathias last_name: Wand - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Torsten full_name: Meier, Torsten id: '344' last_name: Meier orcid: 0000-0001-8864-2072 - first_name: Jens full_name: Förstner, Jens id: '158' last_name: Förstner orcid: 0000-0001-7059-9862 citation: ama: "Wand M, Schindlmayr A, Meier T, Förstner J. Theoretical approach to the ultrafast nonlinear optical response of metal slabs. In: CLEO:2011 - Laser Applications to Photonic Applications\t. OSA Technical Digest. Optical Society of America; 2011. doi:10.1364/CLEO_AT.2011.JTuI59" apa: "Wand, M., Schindlmayr, A., Meier, T., & Förstner, J. (2011). Theoretical approach to the ultrafast nonlinear optical response of metal slabs. CLEO:2011 - Laser Applications to Photonic Applications\t, Article JTuI59. Conference on Lasers and Electro-Optics 2011, Baltimore, Maryland, United States. https://doi.org/10.1364/CLEO_AT.2011.JTuI59" bibtex: "@inproceedings{Wand_Schindlmayr_Meier_Förstner_2011, series={OSA Technical Digest}, title={Theoretical approach to the ultrafast nonlinear optical response of metal slabs}, DOI={10.1364/CLEO_AT.2011.JTuI59}, number={JTuI59}, booktitle={CLEO:2011 - Laser Applications to Photonic Applications\t}, publisher={Optical Society of America}, author={Wand, Mathias and Schindlmayr, Arno and Meier, Torsten and Förstner, Jens}, year={2011}, collection={OSA Technical Digest} }" chicago: "Wand, Mathias, Arno Schindlmayr, Torsten Meier, and Jens Förstner. “Theoretical Approach to the Ultrafast Nonlinear Optical Response of Metal Slabs.” In CLEO:2011 - Laser Applications to Photonic Applications\t. OSA Technical Digest. Optical Society of America, 2011. https://doi.org/10.1364/CLEO_AT.2011.JTuI59." ieee: 'M. Wand, A. Schindlmayr, T. Meier, and J. Förstner, “Theoretical approach to the ultrafast nonlinear optical response of metal slabs,” presented at the Conference on Lasers and Electro-Optics 2011, Baltimore, Maryland, United States, 2011, doi: 10.1364/CLEO_AT.2011.JTuI59.' mla: "Wand, Mathias, et al. “Theoretical Approach to the Ultrafast Nonlinear Optical Response of Metal Slabs.” CLEO:2011 - Laser Applications to Photonic Applications\t, JTuI59, Optical Society of America, 2011, doi:10.1364/CLEO_AT.2011.JTuI59." short: "M. Wand, A. Schindlmayr, T. Meier, J. Förstner, in: CLEO:2011 - Laser Applications to Photonic Applications\t, Optical Society of America, 2011." conference: end_date: 2011-05-06 location: Baltimore, Maryland, United States name: Conference on Lasers and Electro-Optics 2011 start_date: 2011-05-01 date_created: 2018-08-22T10:35:41Z date_updated: 2023-04-20T14:55:23Z ddc: - '530' department: - _id: '293' - _id: '296' - _id: '230' - _id: '15' - _id: '170' - _id: '35' doi: 10.1364/CLEO_AT.2011.JTuI59 external_id: isi: - '000295612403066' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T15:51:37Z date_updated: 2020-08-30T15:02:29Z description: © 2011 Optical Society of America file_id: '18587' file_name: 05951090.pdf file_size: 135730 relation: main_file title: Theoretical approach to the ultrafast nonlinear optical response of metal slabs file_date_updated: 2020-08-30T15:02:29Z has_accepted_license: '1' isi: '1' keyword: - tet_topic_shg language: - iso: eng publication: "CLEO:2011 - Laser Applications to Photonic Applications\t" publication_identifier: eisbn: - 978-1-55752-911-4 isbn: - 978-1-4577-1223-4 issn: - 2160-8989 publication_status: published publisher: Optical Society of America series_title: OSA Technical Digest status: public title: Theoretical approach to the ultrafast nonlinear optical response of metal slabs type: conference user_id: '16199' year: '2011' ... --- _id: '18549' abstract: - lang: eng text: We describe the software package SPEX, which allows first-principles calculations of quasiparticle and collective electronic excitations in solids using techniques from many-body perturbation theory. The implementation is based on the full-potential linearized augmented-plane-wave (FLAPW) method, which treats core and valence electrons on an equal footing and can be applied to a wide range of materials, including transition metals and rare earths. After a discussion of essential features that contribute to the high numerical efficiency of the code, we present illustrative results for quasiparticle band structures calculated within the GW approximation for the electronic self-energy, electron-energy-loss spectra with inter- and intraband transitions as well as local-field effects, and spin-wave spectra of itinerant ferromagnets. In all cases the inclusion of many-body correlation terms leads to very good quantitative agreement with experimental spectroscopies. author: - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Ersoy full_name: Şaşıoğlu, Ersoy last_name: Şaşıoğlu - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel citation: ama: 'Schindlmayr A, Friedrich C, Şaşıoğlu E, Blügel S. First-principles calculation of electronic excitations in solids with SPEX. In: Dolg FM, ed. Modern and Universal First-Principles Methods for Many-Electron Systems in Chemistry and Physics. Vol 3. Progress in Physical Chemistry. München: Oldenbourg; 2010:67-78. doi:10.1524/9783486711639.67' apa: 'Schindlmayr, A., Friedrich, C., Şaşıoğlu, E., & Blügel, S. (2010). First-principles calculation of electronic excitations in solids with SPEX. In F. M. Dolg (Ed.), Modern and Universal First-Principles Methods for Many-Electron Systems in Chemistry and Physics (Vol. 3, pp. 67–78). München: Oldenbourg. https://doi.org/10.1524/9783486711639.67' bibtex: '@inbook{Schindlmayr_Friedrich_Şaşıoğlu_Blügel_2010, place={München}, series={Progress in Physical Chemistry}, title={First-principles calculation of electronic excitations in solids with SPEX}, volume={3}, DOI={10.1524/9783486711639.67}, booktitle={Modern and Universal First-Principles Methods for Many-Electron Systems in Chemistry and Physics}, publisher={Oldenbourg}, author={Schindlmayr, Arno and Friedrich, Christoph and Şaşıoğlu, Ersoy and Blügel, Stefan}, editor={Dolg, Franz MichaelEditor}, year={2010}, pages={67–78}, collection={Progress in Physical Chemistry} }' chicago: 'Schindlmayr, Arno, Christoph Friedrich, Ersoy Şaşıoğlu, and Stefan Blügel. “First-Principles Calculation of Electronic Excitations in Solids with SPEX.” In Modern and Universal First-Principles Methods for Many-Electron Systems in Chemistry and Physics, edited by Franz Michael Dolg, 3:67–78. Progress in Physical Chemistry. München: Oldenbourg, 2010. https://doi.org/10.1524/9783486711639.67.' ieee: 'A. Schindlmayr, C. Friedrich, E. Şaşıoğlu, and S. Blügel, “First-principles calculation of electronic excitations in solids with SPEX,” in Modern and Universal First-Principles Methods for Many-Electron Systems in Chemistry and Physics, vol. 3, F. M. Dolg, Ed. München: Oldenbourg, 2010, pp. 67–78.' mla: Schindlmayr, Arno, et al. “First-Principles Calculation of Electronic Excitations in Solids with SPEX.” Modern and Universal First-Principles Methods for Many-Electron Systems in Chemistry and Physics, edited by Franz Michael Dolg, vol. 3, Oldenbourg, 2010, pp. 67–78, doi:10.1524/9783486711639.67. short: 'A. Schindlmayr, C. Friedrich, E. Şaşıoğlu, S. Blügel, in: F.M. Dolg (Ed.), Modern and Universal First-Principles Methods for Many-Electron Systems in Chemistry and Physics, Oldenbourg, München, 2010, pp. 67–78.' date_created: 2020-08-28T11:03:04Z date_updated: 2022-01-06T06:53:37Z department: - _id: '296' doi: 10.1524/9783486711639.67 editor: - first_name: Franz Michael full_name: Dolg, Franz Michael last_name: Dolg intvolume: ' 3' language: - iso: eng page: 67-78 place: München publication: Modern and Universal First-Principles Methods for Many-Electron Systems in Chemistry and Physics publication_identifier: eisbn: - 978-3-486-71163-9 isbn: - 978-3-486-59827-8 publication_status: published publisher: Oldenbourg quality_controlled: '1' series_title: Progress in Physical Chemistry status: public title: First-principles calculation of electronic excitations in solids with SPEX type: book_chapter user_id: '458' volume: 3 year: '2010' ... --- _id: '18562' abstract: - lang: eng text: "The structural and electronic properties of strained silicon are investigated quantitatively with ab initio computational methods. For this purpose we combine densityfunctional theory within the local‐density approximation and the GW approximation for the electronic self‐energy. From the variation of the total energy as a function of applied strain we obtain the elastic constants, Poisson ratios and related structural parameters, taking a possible internal relaxation fully into account. For biaxial tensile strain in the (001) and (111) planes we then investigate the effects on the electronic band structure. These strain configurations occur in epitaxial silicon films grown on SiGe templates along different crystallographic directions.\r\nThe tetragonal deformation resulting from (001) strain induces a valley splitting that removes the sixfold degeneracy of the conduction‐band minimum. Furthermore, strain in any direction causes the band structure to warp. We present quantitative results for the electron effective mass, derived from the curvature of the conduction band, as a function of strain and discuss the implications for the mobility of the charge carriers. The inclusion of proper self‐energy corrections within the GW approximation in our work not only yields band gaps in much better agreement with experimental measurements than the localdensity approximation, but also predicts slightly larger electron effective masses." article_type: original author: - first_name: Mohammed full_name: Bouhassoune, Mohammed last_name: Bouhassoune - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Bouhassoune M, Schindlmayr A. Electronic structure and effective masses in strained silicon. Physica Status Solidi C. 2010;7(2):460-463. doi:10.1002/pssc.200982470 apa: Bouhassoune, M., & Schindlmayr, A. (2010). Electronic structure and effective masses in strained silicon. Physica Status Solidi C, 7(2), 460–463. https://doi.org/10.1002/pssc.200982470 bibtex: '@article{Bouhassoune_Schindlmayr_2010, title={Electronic structure and effective masses in strained silicon}, volume={7}, DOI={10.1002/pssc.200982470}, number={2}, journal={Physica Status Solidi C}, publisher={Wiley-VCH}, author={Bouhassoune, Mohammed and Schindlmayr, Arno}, year={2010}, pages={460–463} }' chicago: 'Bouhassoune, Mohammed, and Arno Schindlmayr. “Electronic Structure and Effective Masses in Strained Silicon.” Physica Status Solidi C 7, no. 2 (2010): 460–63. https://doi.org/10.1002/pssc.200982470.' ieee: M. Bouhassoune and A. Schindlmayr, “Electronic structure and effective masses in strained silicon,” Physica Status Solidi C, vol. 7, no. 2, pp. 460–463, 2010. mla: Bouhassoune, Mohammed, and Arno Schindlmayr. “Electronic Structure and Effective Masses in Strained Silicon.” Physica Status Solidi C, vol. 7, no. 2, Wiley-VCH, 2010, pp. 460–63, doi:10.1002/pssc.200982470. short: M. Bouhassoune, A. Schindlmayr, Physica Status Solidi C 7 (2010) 460–463. conference: end_date: 2009-07-10 location: Weimar name: 12th International Conference on the Formation of Semiconductor Interfaces start_date: 2009-07-05 date_created: 2020-08-28T11:35:38Z date_updated: 2022-01-06T06:53:39Z ddc: - '530' department: - _id: '296' doi: 10.1002/pssc.200982470 external_id: isi: - '000284313000081' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T14:38:30Z date_updated: 2020-08-30T15:13:32Z description: © 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim file_id: '18582' file_name: pssc.200982470.pdf file_size: 118792 relation: main_file title: Electronic structure and effective masses in strained silicon file_date_updated: 2020-08-30T15:13:32Z has_accepted_license: '1' intvolume: ' 7' isi: '1' issue: '2' language: - iso: eng page: 460-463 publication: Physica Status Solidi C publication_identifier: eissn: - 1610-1642 issn: - 1862-6351 publication_status: published publisher: Wiley-VCH quality_controlled: '1' status: public title: Electronic structure and effective masses in strained silicon type: journal_article user_id: '458' volume: 7 year: '2010' ... --- _id: '13573' abstract: - lang: eng text: Given the vast range of lithium niobate (LiNbO3) applications, the knowledge about its electronic and optical properties is surprisingly limited. The direct band gap of 3.7 eV for the ferroelectric phase – frequently cited in the literature – is concluded from optical experiments. Recent theoretical investigations show that the electronic band‐structure and optical properties are very sensitive to quasiparticle and electron‐hole attraction effects, which were included using the GW approximation for the electron self‐energy and the Bethe‐Salpeter equation respectively, both based on a model screening function. The calculated fundamental gap was found to be at least 1 eV larger than the experimental value. To resolve this discrepancy we performed first‐principles GW calculations for lithium niobate using the full‐potential linearized augmented plane‐wave (FLAPW) method. Thereby we use the parameter‐free random phase approximation for a realistic description of the nonlocal and energydependent screening. This leads to a band gap of about 4.7 (4.2) eV for ferro(para)‐electric lithium niobate. article_type: original author: - first_name: Christian full_name: Thierfelder, Christian last_name: Thierfelder - first_name: Simone full_name: Sanna, Simone last_name: Sanna - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 citation: ama: Thierfelder C, Sanna S, Schindlmayr A, Schmidt WG. Do we know the band gap of lithium niobate? Physica Status Solidi C. 2010;7(2):362-365. doi:10.1002/pssc.200982473 apa: Thierfelder, C., Sanna, S., Schindlmayr, A., & Schmidt, W. G. (2010). Do we know the band gap of lithium niobate? Physica Status Solidi C, 7(2), 362–365. https://doi.org/10.1002/pssc.200982473 bibtex: '@article{Thierfelder_Sanna_Schindlmayr_Schmidt_2010, title={Do we know the band gap of lithium niobate?}, volume={7}, DOI={10.1002/pssc.200982473}, number={2}, journal={Physica Status Solidi C}, publisher={Wiley-VCH}, author={Thierfelder, Christian and Sanna, Simone and Schindlmayr, Arno and Schmidt, Wolf Gero}, year={2010}, pages={362–365} }' chicago: 'Thierfelder, Christian, Simone Sanna, Arno Schindlmayr, and Wolf Gero Schmidt. “Do We Know the Band Gap of Lithium Niobate?” Physica Status Solidi C 7, no. 2 (2010): 362–65. https://doi.org/10.1002/pssc.200982473.' ieee: C. Thierfelder, S. Sanna, A. Schindlmayr, and W. G. Schmidt, “Do we know the band gap of lithium niobate?,” Physica Status Solidi C, vol. 7, no. 2, pp. 362–365, 2010. mla: Thierfelder, Christian, et al. “Do We Know the Band Gap of Lithium Niobate?” Physica Status Solidi C, vol. 7, no. 2, Wiley-VCH, 2010, pp. 362–65, doi:10.1002/pssc.200982473. short: C. Thierfelder, S. Sanna, A. Schindlmayr, W.G. Schmidt, Physica Status Solidi C 7 (2010) 362–365. conference: end_date: 2009-07-10 location: Weimar name: 12th International Conference on the Formation of Semiconductor Interfaces start_date: 2009-07-05 date_created: 2019-10-01T09:18:29Z date_updated: 2022-01-06T06:51:39Z ddc: - '530' department: - _id: '295' - _id: '296' doi: 10.1002/pssc.200982473 external_id: isi: - '000284313000057' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T14:39:40Z date_updated: 2020-08-30T15:07:56Z description: © 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim file_id: '18583' file_name: pssc.200982473.pdf file_size: 212674 relation: main_file title: Do we know the band gap of lithium niobate? file_date_updated: 2020-08-30T15:07:56Z has_accepted_license: '1' intvolume: ' 7' isi: '1' issue: '2' language: - iso: eng page: 362-365 project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing publication: Physica Status Solidi C publication_identifier: eissn: - 1610-1642 issn: - 1862-6351 publication_status: published publisher: Wiley-VCH quality_controlled: '1' status: public title: Do we know the band gap of lithium niobate? type: journal_article user_id: '458' volume: 7 year: '2010' ... --- _id: '18560' abstract: - lang: eng text: We present a computational scheme to study spin excitations in magnetic materials from first principles. The central quantity is the transverse spin susceptibility, from which the complete excitation spectrum, including single-particle spin-flip Stoner excitations and collective spin-wave modes, can be obtained. The susceptibility is derived from many-body perturbation theory and includes dynamic correlation through a summation over ladder diagrams that describe the coupling of electrons and holes with opposite spins. In contrast to earlier studies, we do not use a model potential with adjustable parameters for the electron-hole interaction but employ the random-phase approximation. To reduce the numerical cost for the calculation of the four-point scattering matrix we perform a projection onto maximally localized Wannier functions, which allows us to truncate the matrix efficiently by exploiting the short spatial range of electronic correlation in the partially filled d or f orbitals. Our implementation is based on the full-potential linearized augmented-plane-wave method. Starting from a ground-state calculation within the local-spin-density approximation (LSDA), we first analyze the matrix elements of the screened Coulomb potential in the Wannier basis for the 3d transition-metal series. In particular, we discuss the differences between a constrained nonmagnetic and a proper spin-polarized treatment for the ferromagnets Fe, Co, and Ni. The spectrum of single-particle and collective spin excitations in fcc Ni is then studied in detail. The calculated spin-wave dispersion is in good overall agreement with experimental data and contains both an acoustic and an optical branch for intermediate wave vectors along the [100] direction. In addition, we find evidence for a similar double-peak structure in the spectral function along the [111] direction. To investigate the influence of static correlation we finally consider LSDA+U as an alternative starting point and show that, together with an improved description of the Fermi surface, it yields a more accurate quantitative value for the spin-wave stiffness constant, which is overestimated in the LSDA. article_number: '054434' article_type: original author: - first_name: Ersoy full_name: Şaşıoğlu, Ersoy last_name: Şaşıoğlu - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Frank full_name: Freimuth, Frank last_name: Freimuth - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel citation: ama: Şaşıoğlu E, Schindlmayr A, Friedrich C, Freimuth F, Blügel S. Wannier-function approach to spin excitations in solids. Physical Review B. 2010;81(5). doi:10.1103/PhysRevB.81.054434 apa: Şaşıoğlu, E., Schindlmayr, A., Friedrich, C., Freimuth, F., & Blügel, S. (2010). Wannier-function approach to spin excitations in solids. Physical Review B, 81(5), Article 054434. https://doi.org/10.1103/PhysRevB.81.054434 bibtex: '@article{Şaşıoğlu_Schindlmayr_Friedrich_Freimuth_Blügel_2010, title={Wannier-function approach to spin excitations in solids}, volume={81}, DOI={10.1103/PhysRevB.81.054434}, number={5054434}, journal={Physical Review B}, publisher={American Physical Society}, author={Şaşıoğlu, Ersoy and Schindlmayr, Arno and Friedrich, Christoph and Freimuth, Frank and Blügel, Stefan}, year={2010} }' chicago: Şaşıoğlu, Ersoy, Arno Schindlmayr, Christoph Friedrich, Frank Freimuth, and Stefan Blügel. “Wannier-Function Approach to Spin Excitations in Solids.” Physical Review B 81, no. 5 (2010). https://doi.org/10.1103/PhysRevB.81.054434. ieee: 'E. Şaşıoğlu, A. Schindlmayr, C. Friedrich, F. Freimuth, and S. Blügel, “Wannier-function approach to spin excitations in solids,” Physical Review B, vol. 81, no. 5, Art. no. 054434, 2010, doi: 10.1103/PhysRevB.81.054434.' mla: Şaşıoğlu, Ersoy, et al. “Wannier-Function Approach to Spin Excitations in Solids.” Physical Review B, vol. 81, no. 5, 054434, American Physical Society, 2010, doi:10.1103/PhysRevB.81.054434. short: E. Şaşıoğlu, A. Schindlmayr, C. Friedrich, F. Freimuth, S. Blügel, Physical Review B 81 (2010). date_created: 2020-08-28T11:31:26Z date_updated: 2022-11-11T06:46:09Z ddc: - '530' department: - _id: '296' doi: 10.1103/PhysRevB.81.054434 external_id: arxiv: - '1002.4897' isi: - '000274998000084' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T11:33:17Z date_updated: 2020-08-30T15:06:10Z description: © 2010 American Physical Society file_id: '18561' file_name: PhysRevB.81.054434.pdf file_size: 711970 relation: main_file title: Wannier-function approach to spin excitations in solids file_date_updated: 2020-08-30T15:06:10Z has_accepted_license: '1' intvolume: ' 81' isi: '1' issue: '5' language: - iso: eng oa: '1' publication: Physical Review B publication_identifier: eissn: - 1550-235X issn: - 1098-0121 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: Wannier-function approach to spin excitations in solids type: journal_article user_id: '458' volume: 81 year: '2010' ... --- _id: '18557' abstract: - lang: eng text: We describe the software package SPEX, which allows first-principles calculations of quasiparticle and collective electronic excitations in solids using techniques from many-body perturbation theory. The implementation is based on the full-potential linearized augmented-plane-wave (FLAPW) method, which treats core and valence electrons on an equal footing and can be applied to a wide range of materials, including transition metals and rare earths. After a discussion of essential features that contribute to the high numerical efficiency of the code, we present illustrative results for quasiparticle band structures calculated within the GW approximation for the electronic self-energy, electron-energy-loss spectra with inter- and intraband transitions as well as local-field effects, and spin-wave spectra of itinerant ferromagnets. In all cases the inclusion of many-body correlation terms leads to very good quantitative agreement with experimental spectroscopies. article_type: original author: - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Ersoy full_name: Şaşıoğlu, Ersoy last_name: Şaşıoğlu - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel citation: ama: Schindlmayr A, Friedrich C, Şaşıoğlu E, Blügel S. First-principles calculation of electronic excitations in solids with SPEX. Zeitschrift für Physikalische Chemie. 2010;224(3-4):357-368. doi:10.1524/zpch.2010.6110 apa: Schindlmayr, A., Friedrich, C., Şaşıoğlu, E., & Blügel, S. (2010). First-principles calculation of electronic excitations in solids with SPEX. Zeitschrift Für Physikalische Chemie, 224(3–4), 357–368. https://doi.org/10.1524/zpch.2010.6110 bibtex: '@article{Schindlmayr_Friedrich_Şaşıoğlu_Blügel_2010, title={First-principles calculation of electronic excitations in solids with SPEX}, volume={224}, DOI={10.1524/zpch.2010.6110}, number={3–4}, journal={Zeitschrift für Physikalische Chemie}, publisher={Oldenbourg}, author={Schindlmayr, Arno and Friedrich, Christoph and Şaşıoğlu, Ersoy and Blügel, Stefan}, year={2010}, pages={357–368} }' chicago: 'Schindlmayr, Arno, Christoph Friedrich, Ersoy Şaşıoğlu, and Stefan Blügel. “First-Principles Calculation of Electronic Excitations in Solids with SPEX.” Zeitschrift Für Physikalische Chemie 224, no. 3–4 (2010): 357–68. https://doi.org/10.1524/zpch.2010.6110.' ieee: 'A. Schindlmayr, C. Friedrich, E. Şaşıoğlu, and S. Blügel, “First-principles calculation of electronic excitations in solids with SPEX,” Zeitschrift für Physikalische Chemie, vol. 224, no. 3–4, pp. 357–368, 2010, doi: 10.1524/zpch.2010.6110.' mla: Schindlmayr, Arno, et al. “First-Principles Calculation of Electronic Excitations in Solids with SPEX.” Zeitschrift Für Physikalische Chemie, vol. 224, no. 3–4, Oldenbourg, 2010, pp. 357–68, doi:10.1524/zpch.2010.6110. short: A. Schindlmayr, C. Friedrich, E. Şaşıoğlu, S. Blügel, Zeitschrift Für Physikalische Chemie 224 (2010) 357–368. date_created: 2020-08-28T11:20:50Z date_updated: 2022-11-11T06:42:52Z ddc: - '530' department: - _id: '296' doi: 10.1524/zpch.2010.6110 external_id: arxiv: - '1110.1596' isi: - '000281124800006' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T14:34:10Z date_updated: 2020-08-30T15:04:39Z description: © 2010 Oldenbourg Wissenschaftsverlag, München file_id: '18581' file_name: zpch.2010.6110.pdf file_size: 912086 relation: main_file title: First-principles calculation of electronic excitations in solids with SPEX file_date_updated: 2020-08-30T15:04:39Z has_accepted_license: '1' intvolume: ' 224' isi: '1' issue: 3-4 language: - iso: eng page: 357-368 publication: Zeitschrift für Physikalische Chemie publication_identifier: eissn: - 2196-7156 issn: - 0942-9352 publication_status: published publisher: Oldenbourg quality_controlled: '1' status: public title: First-principles calculation of electronic excitations in solids with SPEX type: journal_article user_id: '458' volume: 224 year: '2010' ... --- _id: '18558' abstract: - lang: eng text: We present an implementation of the GW approximation for the electronic self-energy within the full-potential linearized augmented-plane-wave (FLAPW) method. The algorithm uses an all-electron mixed product basis for the representation of response matrices and related quantities. This basis is derived from the FLAPW basis and is exact for wave-function products. The correlation part of the self-energy is calculated on the imaginary-frequency axis with a subsequent analytic continuation to the real axis. As an alternative we can perform the frequency convolution of the Green function G and the dynamically screened Coulomb interaction W explicitly by a contour integration. The singularity of the bare and screened interaction potentials gives rise to a numerically important self-energy contribution, which we treat analytically to achieve good convergence with respect to the k-point sampling. As numerical realizations of the GW approximation typically suffer from the high computational expense required for the evaluation of the nonlocal and frequency-dependent self-energy, we demonstrate how the algorithm can be made very efficient by exploiting spatial and time-reversal symmetry as well as by applying an optimization of the mixed product basis that retains only the numerically important contributions of the electron-electron interaction. This optimization step reduces the basis size without compromising the accuracy and accelerates the code considerably. Furthermore, we demonstrate that one can employ an extrapolar approximation for high-lying states to reduce the number of empty states that must be taken into account explicitly in the construction of the polarization function and the self-energy. We show convergence tests, CPU timings, and results for prototype semiconductors and insulators as well as ferromagnetic nickel. article_number: '125102' article_type: original author: - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Friedrich C, Blügel S, Schindlmayr A. Efficient implementation of the GW approximation within the all-electron FLAPW method. Physical Review B. 2010;81(12). doi:10.1103/PhysRevB.81.125102 apa: Friedrich, C., Blügel, S., & Schindlmayr, A. (2010). Efficient implementation of the GW approximation within the all-electron FLAPW method. Physical Review B, 81(12), Article 125102. https://doi.org/10.1103/PhysRevB.81.125102 bibtex: '@article{Friedrich_Blügel_Schindlmayr_2010, title={Efficient implementation of the GW approximation within the all-electron FLAPW method}, volume={81}, DOI={10.1103/PhysRevB.81.125102}, number={12125102}, journal={Physical Review B}, publisher={American Physical Society}, author={Friedrich, Christoph and Blügel, Stefan and Schindlmayr, Arno}, year={2010} }' chicago: Friedrich, Christoph, Stefan Blügel, and Arno Schindlmayr. “Efficient Implementation of the GW Approximation within the All-Electron FLAPW Method.” Physical Review B 81, no. 12 (2010). https://doi.org/10.1103/PhysRevB.81.125102. ieee: 'C. Friedrich, S. Blügel, and A. Schindlmayr, “Efficient implementation of the GW approximation within the all-electron FLAPW method,” Physical Review B, vol. 81, no. 12, Art. no. 125102, 2010, doi: 10.1103/PhysRevB.81.125102.' mla: Friedrich, Christoph, et al. “Efficient Implementation of the GW Approximation within the All-Electron FLAPW Method.” Physical Review B, vol. 81, no. 12, 125102, American Physical Society, 2010, doi:10.1103/PhysRevB.81.125102. short: C. Friedrich, S. Blügel, A. Schindlmayr, Physical Review B 81 (2010). date_created: 2020-08-28T11:26:20Z date_updated: 2023-04-20T14:57:10Z ddc: - '530' department: - _id: '296' - _id: '35' - _id: '15' - _id: '170' doi: 10.1103/PhysRevB.81.125102 external_id: arxiv: - '1003.0316' isi: - '000276248900039' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T11:29:11Z date_updated: 2020-08-30T15:06:54Z description: © 2010 American Physical Society file_id: '18559' file_name: PhysRevB.81.125102.pdf file_size: 330212 relation: main_file title: Efficient implementation of the GW approximation within the all-electron FLAPW method file_date_updated: 2020-08-30T15:06:54Z has_accepted_license: '1' intvolume: ' 81' isi: '1' issue: '12' language: - iso: eng oa: '1' publication: Physical Review B publication_identifier: eissn: - 1550-235X issn: - 1098-0121 publication_status: published publisher: American Physical Society quality_controlled: '1' related_material: record: - id: '22761' relation: other status: public status: public title: Efficient implementation of the GW approximation within the all-electron FLAPW method type: journal_article user_id: '16199' volume: 81 year: '2010' ... --- _id: '18632' abstract: - lang: eng text: "We present measurements of the effective electron mass in biaxial tensile strained silicon on insulator (SSOI) material with 1.2 GPa stress and in unstrained SOI. Hall-bar metal oxide semiconductor field effect transistors on 60 nm SSOI and SOI were fabricated and Shubnikov–de Haas oscillations in the temperature range of T=0.4–4 K for magnetic fields of B=0–10 T were measured. The effective electron mass in SSOI and SOI samples was determined as mt=(0.20±0.01)m0. This result is in excellent agreement with first-principles calculations of the\r\neffective electron mass in the presence of strain." article_number: '182101' article_type: original author: - first_name: Sebastian F. full_name: Feste, Sebastian F. last_name: Feste - first_name: Thomas full_name: Schäpers, Thomas last_name: Schäpers - first_name: Dan full_name: Buca, Dan last_name: Buca - first_name: Qing Tai full_name: Zhao, Qing Tai last_name: Zhao - first_name: Joachim full_name: Knoch, Joachim last_name: Knoch - first_name: Mohammed full_name: Bouhassoune, Mohammed last_name: Bouhassoune - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Siegfried full_name: Mantl, Siegfried last_name: Mantl citation: ama: Feste SF, Schäpers T, Buca D, et al. Measurement of effective electron mass in biaxial tensile strained silicon on insulator. Applied Physics Letters. 2009;95(18). doi:10.1063/1.3254330 apa: Feste, S. F., Schäpers, T., Buca, D., Zhao, Q. T., Knoch, J., Bouhassoune, M., … Mantl, S. (2009). Measurement of effective electron mass in biaxial tensile strained silicon on insulator. Applied Physics Letters, 95(18). https://doi.org/10.1063/1.3254330 bibtex: '@article{Feste_Schäpers_Buca_Zhao_Knoch_Bouhassoune_Schindlmayr_Mantl_2009, title={Measurement of effective electron mass in biaxial tensile strained silicon on insulator}, volume={95}, DOI={10.1063/1.3254330}, number={18182101}, journal={Applied Physics Letters}, publisher={American Institute of Physics}, author={Feste, Sebastian F. and Schäpers, Thomas and Buca, Dan and Zhao, Qing Tai and Knoch, Joachim and Bouhassoune, Mohammed and Schindlmayr, Arno and Mantl, Siegfried}, year={2009} }' chicago: Feste, Sebastian F., Thomas Schäpers, Dan Buca, Qing Tai Zhao, Joachim Knoch, Mohammed Bouhassoune, Arno Schindlmayr, and Siegfried Mantl. “Measurement of Effective Electron Mass in Biaxial Tensile Strained Silicon on Insulator.” Applied Physics Letters 95, no. 18 (2009). https://doi.org/10.1063/1.3254330. ieee: S. F. Feste et al., “Measurement of effective electron mass in biaxial tensile strained silicon on insulator,” Applied Physics Letters, vol. 95, no. 18, 2009. mla: Feste, Sebastian F., et al. “Measurement of Effective Electron Mass in Biaxial Tensile Strained Silicon on Insulator.” Applied Physics Letters, vol. 95, no. 18, 182101, American Institute of Physics, 2009, doi:10.1063/1.3254330. short: S.F. Feste, T. Schäpers, D. Buca, Q.T. Zhao, J. Knoch, M. Bouhassoune, A. Schindlmayr, S. Mantl, Applied Physics Letters 95 (2009). date_created: 2020-08-28T22:24:30Z date_updated: 2022-01-06T06:53:49Z ddc: - '530' department: - _id: '296' doi: 10.1063/1.3254330 external_id: isi: - '000271666800034' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T22:28:31Z date_updated: 2020-08-30T15:29:43Z description: © 2009 American Institute of Physics file_id: '18633' file_name: 1.3254330.pdf file_size: 198836 relation: main_file title: Measurement of effective electron mass in biaxial tensile strained silicon on insulator file_date_updated: 2020-08-30T15:29:43Z has_accepted_license: '1' intvolume: ' 95' isi: '1' issue: '18' language: - iso: eng oa: '1' publication: Applied Physics Letters publication_identifier: eissn: - 1077-3118 issn: - 0003-6951 publication_status: published publisher: American Institute of Physics quality_controlled: '1' status: public title: Measurement of effective electron mass in biaxial tensile strained silicon on insulator type: journal_article user_id: '458' volume: 95 year: '2009' ... --- _id: '18634' abstract: - lang: eng text: A computational method to obtain optical conductivities from first principles is presented. It exploits a relation between the conductivity and the complex dielectric function, which is constructed from the full electronic band structure within the random-phase approximation. In contrast to the Drude model, no empirical parameters are used. As interband transitions as well as local-field effects are properly included, the calculated spectra are valid over a wide frequency range. As an illustration I present quantitative results for selected simple metals, noble metals, and ferromagnetic transition metals. The implementation is based on the full-potential linearized augmented-plane-wave method. author: - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Schindlmayr A. Optical conductivity of metals from first principles. In: Chigrin DN, ed. Theoretical and Computational Nanophotonics: Proceedings of the 2nd International Workshop. Vol 1176. AIP Conference Proceedings. American Institute of Physics; 2009:157-159. doi:10.1063/1.3253897' apa: 'Schindlmayr, A. (2009). Optical conductivity of metals from first principles. In D. N. Chigrin (Ed.), Theoretical and Computational Nanophotonics: Proceedings of the 2nd International Workshop (Vol. 1176, Issue 1, pp. 157–159). American Institute of Physics. https://doi.org/10.1063/1.3253897' bibtex: '@inproceedings{Schindlmayr_2009, series={AIP Conference Proceedings}, title={Optical conductivity of metals from first principles}, volume={1176}, DOI={10.1063/1.3253897}, number={1}, booktitle={Theoretical and Computational Nanophotonics: Proceedings of the 2nd International Workshop}, publisher={American Institute of Physics}, author={Schindlmayr, Arno}, editor={Chigrin, Dmitry N.}, year={2009}, pages={157–159}, collection={AIP Conference Proceedings} }' chicago: 'Schindlmayr, Arno. “Optical Conductivity of Metals from First Principles.” In Theoretical and Computational Nanophotonics: Proceedings of the 2nd International Workshop, edited by Dmitry N. Chigrin, 1176:157–59. AIP Conference Proceedings. American Institute of Physics, 2009. https://doi.org/10.1063/1.3253897.' ieee: 'A. Schindlmayr, “Optical conductivity of metals from first principles,” in Theoretical and Computational Nanophotonics: Proceedings of the 2nd International Workshop, Bad Honnef, 2009, vol. 1176, no. 1, pp. 157–159, doi: 10.1063/1.3253897.' mla: 'Schindlmayr, Arno. “Optical Conductivity of Metals from First Principles.” Theoretical and Computational Nanophotonics: Proceedings of the 2nd International Workshop, edited by Dmitry N. Chigrin, vol. 1176, no. 1, American Institute of Physics, 2009, pp. 157–59, doi:10.1063/1.3253897.' short: 'A. Schindlmayr, in: D.N. Chigrin (Ed.), Theoretical and Computational Nanophotonics: Proceedings of the 2nd International Workshop, American Institute of Physics, 2009, pp. 157–159.' conference: end_date: 2009-10-30 location: Bad Honnef name: Theoretical and Computational Nanophotonics start_date: 2009-10-28 date_created: 2020-08-28T22:35:13Z date_updated: 2022-11-11T06:44:03Z ddc: - '530' department: - _id: '296' doi: 10.1063/1.3253897 editor: - first_name: Dmitry N. full_name: Chigrin, Dmitry N. last_name: Chigrin external_id: arxiv: - '1109.2771' isi: - '000280420600055' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T22:42:54Z date_updated: 2020-08-30T15:19:49Z description: © 2009 American Institute of Physics file_id: '18635' file_name: APC000157.pdf file_size: 259756 relation: main_file title: Optical conductivity of metals from first principles file_date_updated: 2020-08-30T15:19:49Z has_accepted_license: '1' intvolume: ' 1176' isi: '1' issue: '1' language: - iso: eng oa: '1' page: 157-159 publication: 'Theoretical and Computational Nanophotonics: Proceedings of the 2nd International Workshop' publication_identifier: eissn: - 1551-7616 isbn: - 978-0-7354-0715-2 issn: - 0094-243X publication_status: published publisher: American Institute of Physics quality_controlled: '1' series_title: AIP Conference Proceedings status: public title: Optical conductivity of metals from first principles type: conference user_id: '458' volume: 1176 year: '2009' ... --- _id: '18636' abstract: - lang: eng text: We derive formulas for the Coulomb matrix within the full-potential linearized augmented-plane-wave (FLAPW) method. The Coulomb matrix is a central ingredient in implementations of many-body perturbation theory, such as the Hartree–Fock and GW approximations for the electronic self-energy or the random-phase approximation for the dielectric function. It is represented in the mixed product basis, which combines numerical muffin-tin functions and interstitial plane waves constructed from products of FLAPW basis functions. The interstitial plane waves are here expanded with the Rayleigh formula. The resulting algorithm is very efficient in terms of both computational cost and accuracy and is superior to an implementation with the Fourier transform of the step function. In order to allow an analytic treatment of the divergence at k=0 in reciprocal space, we expand the Coulomb matrix analytically around this point without resorting to a projection onto plane waves. Without additional approximations, we then apply a basis transformation that diagonalizes the Coulomb matrix and confines the divergence to a single eigenvalue. At the same time, response matrices like the dielectric function separate into head, wings, and body with the same mathematical properties as in a plane-wave basis. As an illustration we apply the formulas to electron-energy-loss spectra (EELS) for nickel at different k vectors including k=0. The convergence of the spectra towards the result at k=0 is clearly seen. Our all-electron treatment also allows to include transitions from 3s and 3p core states in the EELS spectrum that give rise to a shallow peak at high energies and lead to good agreement with experiment. article_type: original author: - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel citation: ama: Friedrich C, Schindlmayr A, Blügel S. Efficient calculation of the Coulomb matrix and its expansion around k=0 within the FLAPW method. Computer Physics Communications. 2009;180(3):347-359. doi:10.1016/j.cpc.2008.10.009 apa: Friedrich, C., Schindlmayr, A., & Blügel, S. (2009). Efficient calculation of the Coulomb matrix and its expansion around k=0 within the FLAPW method. Computer Physics Communications, 180(3), 347–359. https://doi.org/10.1016/j.cpc.2008.10.009 bibtex: '@article{Friedrich_Schindlmayr_Blügel_2009, title={Efficient calculation of the Coulomb matrix and its expansion around k=0 within the FLAPW method}, volume={180}, DOI={10.1016/j.cpc.2008.10.009}, number={3}, journal={Computer Physics Communications}, publisher={Elsevier}, author={Friedrich, Christoph and Schindlmayr, Arno and Blügel, Stefan}, year={2009}, pages={347–359} }' chicago: 'Friedrich, Christoph, Arno Schindlmayr, and Stefan Blügel. “Efficient Calculation of the Coulomb Matrix and Its Expansion around K=0 within the FLAPW Method.” Computer Physics Communications 180, no. 3 (2009): 347–59. https://doi.org/10.1016/j.cpc.2008.10.009.' ieee: 'C. Friedrich, A. Schindlmayr, and S. Blügel, “Efficient calculation of the Coulomb matrix and its expansion around k=0 within the FLAPW method,” Computer Physics Communications, vol. 180, no. 3, pp. 347–359, 2009, doi: 10.1016/j.cpc.2008.10.009.' mla: Friedrich, Christoph, et al. “Efficient Calculation of the Coulomb Matrix and Its Expansion around K=0 within the FLAPW Method.” Computer Physics Communications, vol. 180, no. 3, Elsevier, 2009, pp. 347–59, doi:10.1016/j.cpc.2008.10.009. short: C. Friedrich, A. Schindlmayr, S. Blügel, Computer Physics Communications 180 (2009) 347–359. date_created: 2020-08-28T22:50:49Z date_updated: 2022-11-11T06:47:10Z ddc: - '530' department: - _id: '296' doi: 10.1016/j.cpc.2008.10.009 external_id: arxiv: - '0811.2363' isi: - '000264735800002' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-10-05T10:35:14Z date_updated: 2020-10-05T10:41:07Z description: © 2008 Elsevier B.V. file_id: '19875' file_name: 1-s2.0-S0010465508003664-main.pdf file_size: 311274 relation: main_file title: Efficient calculation of the Coulomb matrix and its expansion around k=0 within the FLAPW method file_date_updated: 2020-10-05T10:41:07Z has_accepted_license: '1' intvolume: ' 180' isi: '1' issue: '3' language: - iso: eng page: 347-359 publication: Computer Physics Communications publication_identifier: issn: - 0010-4655 publication_status: published publisher: Elsevier quality_controlled: '1' status: public title: Efficient calculation of the Coulomb matrix and its expansion around k=0 within the FLAPW method type: journal_article user_id: '458' volume: 180 year: '2009' ... --- _id: '18564' abstract: - lang: eng text: 'In the context of photoelectron spectroscopy, the GW approach has developed into the method of choice for computing excitation spectra of weakly correlated bulk systems and their surfaces. To employ the established computational schemes that have been developed for three-dimensional crystals, two-dimensional systems are typically treated in the repeated-slab approach. In this work we critically examine this approach and identify three important aspects for which the treatment of long-range screening in two dimensions differs from the bulk: (1) anisotropy of the macroscopic screening, (2) k-point sampling parallel to the surface, (3) periodic repetition and slab-slab interaction. For prototypical semiconductor (silicon) and ionic (NaCl) thin films we quantify the individual contributions of points (1) to (3) and develop robust and efficient correction schemes derived from the classic theory of dielectric screening.' article_number: '235428' article_type: original author: - first_name: Christoph full_name: Freysoldt, Christoph last_name: Freysoldt - first_name: Philipp full_name: Eggert, Philipp last_name: Eggert - first_name: Patrick full_name: Rinke, Patrick last_name: Rinke - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Matthias full_name: Scheffler, Matthias last_name: Scheffler citation: ama: 'Freysoldt C, Eggert P, Rinke P, Schindlmayr A, Scheffler M. Screening in two dimensions: GW calculations for surfaces and thin films using the repeated-slab approach. Physical Review B. 2008;77(23). doi:10.1103/PhysRevB.77.235428' apa: 'Freysoldt, C., Eggert, P., Rinke, P., Schindlmayr, A., & Scheffler, M. (2008). Screening in two dimensions: GW calculations for surfaces and thin films using the repeated-slab approach. Physical Review B, 77(23), Article 235428. https://doi.org/10.1103/PhysRevB.77.235428' bibtex: '@article{Freysoldt_Eggert_Rinke_Schindlmayr_Scheffler_2008, title={Screening in two dimensions: GW calculations for surfaces and thin films using the repeated-slab approach}, volume={77}, DOI={10.1103/PhysRevB.77.235428}, number={23235428}, journal={Physical Review B}, publisher={American Physical Society}, author={Freysoldt, Christoph and Eggert, Philipp and Rinke, Patrick and Schindlmayr, Arno and Scheffler, Matthias}, year={2008} }' chicago: 'Freysoldt, Christoph, Philipp Eggert, Patrick Rinke, Arno Schindlmayr, and Matthias Scheffler. “Screening in Two Dimensions: GW Calculations for Surfaces and Thin Films Using the Repeated-Slab Approach.” Physical Review B 77, no. 23 (2008). https://doi.org/10.1103/PhysRevB.77.235428.' ieee: 'C. Freysoldt, P. Eggert, P. Rinke, A. Schindlmayr, and M. Scheffler, “Screening in two dimensions: GW calculations for surfaces and thin films using the repeated-slab approach,” Physical Review B, vol. 77, no. 23, Art. no. 235428, 2008, doi: 10.1103/PhysRevB.77.235428.' mla: 'Freysoldt, Christoph, et al. “Screening in Two Dimensions: GW Calculations for Surfaces and Thin Films Using the Repeated-Slab Approach.” Physical Review B, vol. 77, no. 23, 235428, American Physical Society, 2008, doi:10.1103/PhysRevB.77.235428.' short: C. Freysoldt, P. Eggert, P. Rinke, A. Schindlmayr, M. Scheffler, Physical Review B 77 (2008). date_created: 2020-08-28T11:50:14Z date_updated: 2022-11-11T06:48:18Z ddc: - '530' department: - _id: '296' doi: 10.1103/PhysRevB.77.235428 external_id: arxiv: - '0801.1714' isi: - '000257289500118' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T11:51:42Z date_updated: 2020-08-30T15:32:46Z description: Creative Commons Attribution 3.0 Unported Public License (CC BY 3.0) file_id: '18565' file_name: PhysRevB.77.235428.pdf file_size: 286723 relation: main_file title: 'Screening in two dimensions: GW calculations for surfaces and thin films using the repeated-slab approach' file_date_updated: 2020-08-30T15:32:46Z has_accepted_license: '1' intvolume: ' 77' isi: '1' issue: '23' language: - iso: eng oa: '1' publication: Physical Review B publication_identifier: eissn: - 1550-235X issn: - 1098-0121 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: 'Screening in two dimensions: GW calculations for surfaces and thin films using the repeated-slab approach' type: journal_article user_id: '458' volume: 77 year: '2008' ...