--- _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 license: https://creativecommons.org/licenses/by/3.0/ 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' ...