--- _id: '10030' abstract: - lang: eng text: The vibrational properties of stoichiometric LiNbO3 are analyzed within density-functional perturbation theory in order to obtain the complete phonon dispersion of the material. The phonon density of states of the ferroelectric (paraelectric) phase shows two (one) distinct band gaps separating the high-frequency (~800 cm−1) optical branches from the continuum of acoustic and lower optical phonon states. This result leads to specific heat capacites in close agreement with experimental measurements in the range 0–350 K and a Debye temperature of 574 K. The calculated zero-point renormalization of the electronic Kohn–Sham eigenvalues reveals a strong dependence on the phonon wave vectors, especially near Γ. Integrated over all phonon modes, our results indicate a vibrational correction of the electronic band gap of 0.41 eV at 0 K, which is in excellent agreement with the extrapolated temperature-dependent measurements. article_number: '385402' article_type: original author: - first_name: Michael full_name: Friedrich, Michael last_name: Friedrich - first_name: Arthur full_name: Riefer, Arthur last_name: Riefer - first_name: Simone full_name: Sanna, Simone last_name: Sanna - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Friedrich M, Riefer A, Sanna S, Schmidt WG, Schindlmayr A. Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory. Journal of Physics: Condensed Matter. 2015;27(38). doi:10.1088/0953-8984/27/38/385402' apa: 'Friedrich, M., Riefer, A., Sanna, S., Schmidt, W. G., & Schindlmayr, A. (2015). Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory. Journal of Physics: Condensed Matter, 27(38). https://doi.org/10.1088/0953-8984/27/38/385402' bibtex: '@article{Friedrich_Riefer_Sanna_Schmidt_Schindlmayr_2015, title={Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory}, volume={27}, DOI={10.1088/0953-8984/27/38/385402}, number={38385402}, journal={Journal of Physics: Condensed Matter}, publisher={IOP Publishing}, author={Friedrich, Michael and Riefer, Arthur and Sanna, Simone and Schmidt, Wolf Gero and Schindlmayr, Arno}, year={2015} }' chicago: 'Friedrich, Michael, Arthur Riefer, Simone Sanna, Wolf Gero Schmidt, and Arno Schindlmayr. “Phonon Dispersion and Zero-Point Renormalization of LiNbO3 from Density-Functional Perturbation Theory.” Journal of Physics: Condensed Matter 27, no. 38 (2015). https://doi.org/10.1088/0953-8984/27/38/385402.' ieee: 'M. Friedrich, A. Riefer, S. Sanna, W. G. Schmidt, and A. Schindlmayr, “Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory,” Journal of Physics: Condensed Matter, vol. 27, no. 38, 2015.' mla: 'Friedrich, Michael, et al. “Phonon Dispersion and Zero-Point Renormalization of LiNbO3 from Density-Functional Perturbation Theory.” Journal of Physics: Condensed Matter, vol. 27, no. 38, 385402, IOP Publishing, 2015, doi:10.1088/0953-8984/27/38/385402.' short: 'M. Friedrich, A. Riefer, S. Sanna, W.G. Schmidt, A. Schindlmayr, Journal of Physics: Condensed Matter 27 (2015).' date_created: 2019-05-29T08:41:18Z date_updated: 2022-01-06T06:50:27Z ddc: - '530' department: - _id: '295' - _id: '296' - _id: '230' - _id: '429' doi: 10.1088/0953-8984/27/38/385402 external_id: isi: - '000362549700004' pmid: - '26337951' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T14:24:23Z date_updated: 2020-08-30T14:46:56Z description: © 2015 IOP Publishing Ltd file_id: '18578' file_name: Friedrich_2015_J._Phys. _Condens._Matter_27_385402.pdf file_size: 1793430 relation: main_file title: Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory file_date_updated: 2020-08-30T14:46:56Z has_accepted_license: '1' intvolume: ' 27' isi: '1' issue: '38' language: - iso: eng pmid: '1' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing - _id: '53' name: TRR 142 - _id: '55' name: TRR 142 - Project Area B - _id: '69' name: TRR 142 - Subproject B4 publication: 'Journal of Physics: Condensed Matter' publication_identifier: eissn: - 1361-648X issn: - 0953-8984 publication_status: published publisher: IOP Publishing quality_controlled: '1' status: public title: Phonon dispersion and zero-point renormalization of LiNbO3 from density-functional perturbation theory type: journal_article user_id: '458' volume: 27 year: '2015' ... --- _id: '18470' abstract: - lang: eng text: Using ab initio computational methods, we study the structural and electronic properties of strained silicon, which has emerged as a promising technology to improve the performance of silicon-based metal-oxide-semiconductor field-effect transistors. In particular, higher electron mobilities are observed in n-doped samples with monoclinic strain along the [110] direction, and experimental evidence relates this to changes in the effective mass as well as the scattering rates. To assess the relative importance of these two factors, we combine density-functional theory in the local-density approximation with the GW approximation for the electronic self-energy and investigate the effect of uniaxial and biaxial strains along the [110] direction on the structural and electronic properties of Si. Longitudinal and transverse components of the electron effective mass as a function of the strain are derived from fits to the quasiparticle band structure and a diagonalization of the full effective-mass tensor. The changes in the effective masses and the energy splitting of the conduction-band valleys for uniaxial and biaxial strains as well as their impact on the electron mobility are analyzed. The self-energy corrections within GW lead to band gaps in excellent agreement with experimental measurements and slightly larger effective masses than in the local-density approximation. article_number: '453125' article_type: original author: - first_name: Mohammed full_name: Bouhassoune, Mohammed last_name: Bouhassoune - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Bouhassoune M, Schindlmayr A. Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon. Advances in Condensed Matter Physics. 2015;2015. doi:10.1155/2015/453125 apa: Bouhassoune, M., & Schindlmayr, A. (2015). Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon. Advances in Condensed Matter Physics, 2015, Article 453125. https://doi.org/10.1155/2015/453125 bibtex: '@article{Bouhassoune_Schindlmayr_2015, title={Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon}, volume={2015}, DOI={10.1155/2015/453125}, number={453125}, journal={Advances in Condensed Matter Physics}, publisher={Hindawi}, author={Bouhassoune, Mohammed and Schindlmayr, Arno}, year={2015} }' chicago: Bouhassoune, Mohammed, and Arno Schindlmayr. “Ab Initio Study of Strain Effects on the Quasiparticle Bands and Effective Masses in Silicon.” Advances in Condensed Matter Physics 2015 (2015). https://doi.org/10.1155/2015/453125. ieee: 'M. Bouhassoune and A. Schindlmayr, “Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon,” Advances in Condensed Matter Physics, vol. 2015, Art. no. 453125, 2015, doi: 10.1155/2015/453125.' mla: Bouhassoune, Mohammed, and Arno Schindlmayr. “Ab Initio Study of Strain Effects on the Quasiparticle Bands and Effective Masses in Silicon.” Advances in Condensed Matter Physics, vol. 2015, 453125, Hindawi, 2015, doi:10.1155/2015/453125. short: M. Bouhassoune, A. Schindlmayr, Advances in Condensed Matter Physics 2015 (2015). date_created: 2020-08-27T20:45:37Z date_updated: 2022-02-04T13:41:37Z ddc: - '530' department: - _id: '296' doi: 10.1155/2015/453125 external_id: isi: - '000350656500001' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T09:42:44Z date_updated: 2020-08-30T14:45:29Z description: Creative Commons Attribution 3.0 Unported Public License (CC BY 3.0) file_id: '18540' file_name: 453125.pdf file_size: 560248 relation: main_file title: Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon file_date_updated: 2020-08-30T14:45:29Z has_accepted_license: '1' intvolume: ' 2015' isi: '1' language: - iso: eng oa: '1' publication: Advances in Condensed Matter Physics publication_identifier: eissn: - 1687-8124 issn: - 1687-8108 publication_status: published publisher: Hindawi quality_controlled: '1' status: public title: Ab initio study of strain effects on the quasiparticle bands and effective masses in silicon type: journal_article user_id: '458' volume: 2015 year: '2015' ... --- _id: '18471' abstract: - lang: eng text: Collective spin excitations form a fundamental class of excitations in magnetic materials. As their energy reaches down to only a few meV, they are present at all temperatures and substantially influence the properties of magnetic systems. To study the spin excitations in solids from first principles, we have developed a computational scheme based on many-body perturbation theory within the full-potential linearized augmented plane-wave (FLAPW) method. The main quantity of interest is the dynamical transverse spin susceptibility or magnetic response function, from which magnetic excitations, including single-particle spin-flip Stoner excitations and collective spin-wave modes as well as their lifetimes, can be obtained. In order to describe spin waves we include appropriate vertex corrections in the form of a multiple-scattering T matrix, which describes the coupling of electrons and holes with different spins. The electron–hole interaction incorporates the screening of the many-body system within the random-phase approximation. To reduce the numerical cost in evaluating the four-point T matrix, we exploit a transformation to maximally localized Wannier functions that takes advantage of the short spatial range of electronic correlation in the partially filled d or f orbitals of magnetic materials. The theory and the implementation are discussed in detail. In particular, we show how the magnetic response function can be evaluated for arbitrary k points. This enables the calculation of smooth dispersion curves, allowing one to study fine details in the k dependence of the spin-wave spectra. We also demonstrate how spatial and time-reversal symmetry can be exploited to accelerate substantially the computation of the four-point quantities. As an illustration, we present spin-wave spectra and dispersions for the elementary ferromagnet bcc Fe, B2-type tetragonal FeCo, and CrO2 calculated with our scheme. The results are in good agreement with available experimental data. author: - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Ersoy full_name: Şaşıoğlu, Ersoy last_name: Şaşıoğlu - first_name: Mathias full_name: Müller, Mathias last_name: Müller - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel citation: ama: 'Friedrich C, Şaşıoğlu E, Müller M, Schindlmayr A, Blügel S. Spin excitations in solids from many-body perturbation theory. In: Di Valentin C, Botti S, Cococcioni M, eds. First Principles Approaches to Spectroscopic Properties of Complex Materials. Vol 347. Topics in Current Chemistry. Berlin, Heidelberg: Springer; 2014:259-301. doi:10.1007/128_2013_518' apa: 'Friedrich, C., Şaşıoğlu, E., Müller, M., Schindlmayr, A., & Blügel, S. (2014). Spin excitations in solids from many-body perturbation theory. In C. Di Valentin, S. Botti, & M. Cococcioni (Eds.), First Principles Approaches to Spectroscopic Properties of Complex Materials (Vol. 347, pp. 259–301). Berlin, Heidelberg: Springer. https://doi.org/10.1007/128_2013_518' bibtex: '@inbook{Friedrich_Şaşıoğlu_Müller_Schindlmayr_Blügel_2014, place={Berlin, Heidelberg}, series={ Topics in Current Chemistry}, title={Spin excitations in solids from many-body perturbation theory}, volume={347}, DOI={10.1007/128_2013_518}, booktitle={First Principles Approaches to Spectroscopic Properties of Complex Materials}, publisher={Springer}, author={Friedrich, Christoph and Şaşıoğlu, Ersoy and Müller, Mathias and Schindlmayr, Arno and Blügel, Stefan}, editor={Di Valentin, Cristiana and Botti, Silvana and Cococcioni, MatteoEditors}, year={2014}, pages={259–301}, collection={ Topics in Current Chemistry} }' chicago: 'Friedrich, Christoph, Ersoy Şaşıoğlu, Mathias Müller, Arno Schindlmayr, and Stefan Blügel. “Spin Excitations in Solids from Many-Body Perturbation Theory.” In First Principles Approaches to Spectroscopic Properties of Complex Materials, edited by Cristiana Di Valentin, Silvana Botti, and Matteo Cococcioni, 347:259–301. Topics in Current Chemistry. Berlin, Heidelberg: Springer, 2014. https://doi.org/10.1007/128_2013_518.' ieee: 'C. Friedrich, E. Şaşıoğlu, M. Müller, A. Schindlmayr, and S. Blügel, “Spin excitations in solids from many-body perturbation theory,” in First Principles Approaches to Spectroscopic Properties of Complex Materials, vol. 347, C. Di Valentin, S. Botti, and M. Cococcioni, Eds. Berlin, Heidelberg: Springer, 2014, pp. 259–301.' mla: Friedrich, Christoph, et al. “Spin Excitations in Solids from Many-Body Perturbation Theory.” First Principles Approaches to Spectroscopic Properties of Complex Materials, edited by Cristiana Di Valentin et al., vol. 347, Springer, 2014, pp. 259–301, doi:10.1007/128_2013_518. short: 'C. Friedrich, E. Şaşıoğlu, M. Müller, A. Schindlmayr, S. Blügel, in: C. Di Valentin, S. Botti, M. Cococcioni (Eds.), First Principles Approaches to Spectroscopic Properties of Complex Materials, Springer, Berlin, Heidelberg, 2014, pp. 259–301.' date_created: 2020-08-27T21:00:45Z date_updated: 2022-01-06T06:53:34Z ddc: - '530' department: - _id: '296' doi: 10.1007/128_2013_518 editor: - first_name: Cristiana full_name: Di Valentin, Cristiana last_name: Di Valentin - first_name: Silvana full_name: Botti, Silvana last_name: Botti - first_name: Matteo full_name: Cococcioni, Matteo last_name: Cococcioni external_id: isi: - '000356811000008' pmid: - '24577607' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T15:19:57Z date_updated: 2020-08-30T14:48:45Z description: © 2014 Springer-Verlag, Berlin, Heidelberg file_id: '18584' file_name: Friedrich2014_Chapter_SpinExcitationsInSolidsFromMan.pdf file_size: 1061365 relation: main_file title: Spin excitations in solids from many-body perturbation theory file_date_updated: 2020-08-30T14:48:45Z has_accepted_license: '1' intvolume: ' 347' isi: '1' language: - iso: eng page: 259-301 place: Berlin, Heidelberg pmid: '1' publication: First Principles Approaches to Spectroscopic Properties of Complex Materials publication_identifier: eisbn: - 978-3-642-55068-3 eissn: - 1436-5049 isbn: - 978-3-642-55067-6 issn: - 0340-1022 publication_status: published publisher: Springer quality_controlled: '1' series_title: ' Topics in Current Chemistry' status: public title: Spin excitations in solids from many-body perturbation theory type: book_chapter user_id: '458' volume: 347 year: '2014' ... --- _id: '18472' abstract: - lang: eng text: Many-body perturbation theory is a well-established ab initio electronic-structure method based on Green functions. Although computationally more demanding than density functional theory, it has the distinct advantage that the exact expressions for all relevant observables, including the ground-state total energy, in terms of the Green function are known explicitly. The most important application, however, lies in the calculation of excited states, whose energies correspond directly to the poles of the Green function in the complex frequency plane. The accuracy of results obtained within this framework is only limited by the choice of the exchange-correlation self-energy, which must still be approximated in actual implementations. In this respect, the GW approximation has proved highly successful for systems governed by the Coulomb interaction. It yields band structures of solids, including the band gaps of semiconductors, as well as atomic and molecular ionization energies in very good quantitative agreement with experimental photoemission data. author: - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Schindlmayr A. The GW approximation for the electronic self-energy. In: Bach V, Delle Site L, eds. Many-Electron Approaches in Physics, Chemistry and Mathematics. Vol 29. Mathematical Physics Studies. Cham: Springer; 2014:343-357. doi:10.1007/978-3-319-06379-9_19' apa: 'Schindlmayr, A. (2014). The GW approximation for the electronic self-energy. In V. Bach & L. Delle Site (Eds.), Many-Electron Approaches in Physics, Chemistry and Mathematics (Vol. 29, pp. 343–357). Cham: Springer. https://doi.org/10.1007/978-3-319-06379-9_19' bibtex: '@inbook{Schindlmayr_2014, place={Cham}, series={ Mathematical Physics Studies}, title={The GW approximation for the electronic self-energy}, volume={29}, DOI={10.1007/978-3-319-06379-9_19}, booktitle={Many-Electron Approaches in Physics, Chemistry and Mathematics}, publisher={Springer}, author={Schindlmayr, Arno}, editor={Bach, Volker and Delle Site, LuigiEditors}, year={2014}, pages={343–357}, collection={ Mathematical Physics Studies} }' chicago: 'Schindlmayr, Arno. “The GW Approximation for the Electronic Self-Energy.” In Many-Electron Approaches in Physics, Chemistry and Mathematics, edited by Volker Bach and Luigi Delle Site, 29:343–57. Mathematical Physics Studies. Cham: Springer, 2014. https://doi.org/10.1007/978-3-319-06379-9_19.' ieee: 'A. Schindlmayr, “The GW approximation for the electronic self-energy,” in Many-Electron Approaches in Physics, Chemistry and Mathematics, vol. 29, V. Bach and L. Delle Site, Eds. Cham: Springer, 2014, pp. 343–357.' mla: Schindlmayr, Arno. “The GW Approximation for the Electronic Self-Energy.” Many-Electron Approaches in Physics, Chemistry and Mathematics, edited by Volker Bach and Luigi Delle Site, vol. 29, Springer, 2014, pp. 343–57, doi:10.1007/978-3-319-06379-9_19. short: 'A. Schindlmayr, in: V. Bach, L. Delle Site (Eds.), Many-Electron Approaches in Physics, Chemistry and Mathematics, Springer, Cham, 2014, pp. 343–357.' date_created: 2020-08-27T21:11:43Z date_updated: 2022-01-06T06:53:34Z ddc: - '530' department: - _id: '296' doi: 10.1007/978-3-319-06379-9_19 editor: - first_name: Volker full_name: Bach, Volker last_name: Bach - first_name: Luigi full_name: Delle Site, Luigi last_name: Delle Site file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T15:25:10Z date_updated: 2020-08-30T14:50:18Z description: © 2014 Springer International Publishing, Switzerland file_id: '18585' file_name: Schindlmayr2014_Chapter_TheGWApproximationForTheElectr.pdf file_size: 309579 relation: main_file title: The GW approximation for the electronic self-energy file_date_updated: 2020-08-30T14:50:18Z has_accepted_license: '1' intvolume: ' 29' language: - iso: eng page: 343-357 place: Cham publication: Many-Electron Approaches in Physics, Chemistry and Mathematics publication_identifier: eisbn: - 978-3-319-06379-9 eissn: - 2352-3905 isbn: - 978-3-319-06378-2 issn: - 0921-3767 publication_status: published publisher: Springer quality_controlled: '1' series_title: ' Mathematical Physics Studies' status: public title: The GW approximation for the electronic self-energy type: book_chapter user_id: '458' volume: 29 year: '2014' ... --- _id: '18473' abstract: - lang: eng text: We investigate the band dispersion and related electronic properties of picene single crystals within the GW approximation for the electronic self-energy. The width of the upper highest occupied molecular orbital (HOMOu) band along the Γ–Y direction, corresponding to the b crystal axis in real space along which the molecules are stacked, is determined to be 0.60 eV and thus 0.11 eV larger than the value obtained from density-functional theory. As in our recent study of rubrene using the same methodology [S. Yanagisawa, Y. Morikawa, and A. Schindlmayr, Phys. Rev. B 88, 115438 (2013)], this increase in the bandwidth is due to the strong variation of the GW self-energy correction across the Brillouin zone, which in turn reflects the increasing hybridization of the HOMOu states of neighboring picene molecules from Γ to Y. In contrast, the width of the lower HOMO (HOMOl) band along Γ–Y remains almost unchanged, consistent with the fact that the HOMOl(Γ) and HOMOl(Y) states exhibit the same degree of hybridization, so that the nodal structure of the wave functions and the matrix elements of the self-energy correction are very similar. article_number: 05FY02 article_type: original author: - first_name: Susumu full_name: Yanagisawa, Susumu last_name: Yanagisawa - first_name: Yoshitada full_name: Morikawa, Yoshitada last_name: Morikawa - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Yanagisawa S, Morikawa Y, Schindlmayr A. Theoretical investigation of the band structure of picene single crystals within the GW approximation. Japanese Journal of Applied Physics. 2014;53(5S1). doi:10.7567/jjap.53.05fy02 apa: Yanagisawa, S., Morikawa, Y., & Schindlmayr, A. (2014). Theoretical investigation of the band structure of picene single crystals within the GW approximation. Japanese Journal of Applied Physics, 53(5S1). https://doi.org/10.7567/jjap.53.05fy02 bibtex: '@article{Yanagisawa_Morikawa_Schindlmayr_2014, title={Theoretical investigation of the band structure of picene single crystals within the GW approximation}, volume={53}, DOI={10.7567/jjap.53.05fy02}, number={5S105FY02}, journal={Japanese Journal of Applied Physics}, publisher={IOP Publishing and The Japan Society of Applied Physics}, author={Yanagisawa, Susumu and Morikawa, Yoshitada and Schindlmayr, Arno}, year={2014} }' chicago: Yanagisawa, Susumu, Yoshitada Morikawa, and Arno Schindlmayr. “Theoretical Investigation of the Band Structure of Picene Single Crystals within the GW Approximation.” Japanese Journal of Applied Physics 53, no. 5S1 (2014). https://doi.org/10.7567/jjap.53.05fy02. ieee: S. Yanagisawa, Y. Morikawa, and A. Schindlmayr, “Theoretical investigation of the band structure of picene single crystals within the GW approximation,” Japanese Journal of Applied Physics, vol. 53, no. 5S1, 2014. mla: Yanagisawa, Susumu, et al. “Theoretical Investigation of the Band Structure of Picene Single Crystals within the GW Approximation.” Japanese Journal of Applied Physics, vol. 53, no. 5S1, 05FY02, IOP Publishing and The Japan Society of Applied Physics, 2014, doi:10.7567/jjap.53.05fy02. short: S. Yanagisawa, Y. Morikawa, A. Schindlmayr, Japanese Journal of Applied Physics 53 (2014). date_created: 2020-08-27T21:21:24Z date_updated: 2022-01-06T06:53:34Z ddc: - '530' department: - _id: '296' doi: 10.7567/jjap.53.05fy02 external_id: isi: - '000338316200158' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T14:28:20Z date_updated: 2020-08-30T14:52:27Z description: © 2014 The Japan Society of Applied Physics file_id: '18579' file_name: Yanagisawa_2014_Jpn._J._Appl._Phys._53_05FY02.pdf file_size: 588607 relation: main_file title: Theoretical investigation of the band structure of picene single crystals within the GW approximation file_date_updated: 2020-08-30T14:52:27Z has_accepted_license: '1' intvolume: ' 53' isi: '1' issue: 5S1 language: - iso: eng publication: Japanese Journal of Applied Physics publication_identifier: eissn: - 1347-4065 issn: - 0021-4922 publication_status: published publisher: IOP Publishing and The Japan Society of Applied Physics quality_controlled: '1' status: public title: Theoretical investigation of the band structure of picene single crystals within the GW approximation type: journal_article user_id: '458' volume: 53 year: '2014' ... --- _id: '18474' author: - first_name: Christoph full_name: Friedrich, Christoph last_name: Friedrich - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Friedrich C, Schindlmayr A. Many-body perturbation theory: The GW approximation. In: Blügel S, Helbig N, Meden V, Wortmann D, eds. Computing Solids: Models, Ab Initio Methods and Supercomputing. Vol 74. Key Technologies. Jülich: Forschungszentrum Jülich; 2014:A4.1-A4.21.' apa: 'Friedrich, C., & Schindlmayr, A. (2014). Many-body perturbation theory: The GW approximation. In S. Blügel, N. Helbig, V. Meden, & D. Wortmann (Eds.), Computing Solids: Models, ab initio Methods and Supercomputing (Vol. 74, p. A4.1-A4.21). Jülich: Forschungszentrum Jülich.' bibtex: '@inbook{Friedrich_Schindlmayr_2014, place={Jülich}, series={Key Technologies}, title={Many-body perturbation theory: The GW approximation}, volume={74}, booktitle={Computing Solids: Models, ab initio Methods and Supercomputing}, publisher={Forschungszentrum Jülich}, author={Friedrich, Christoph and Schindlmayr, Arno}, editor={Blügel, Stefan and Helbig, Nicole and Meden, Volker and Wortmann, DanielEditors}, year={2014}, pages={A4.1-A4.21}, collection={Key Technologies} }' chicago: 'Friedrich, Christoph, and Arno Schindlmayr. “Many-Body Perturbation Theory: The GW Approximation.” In Computing Solids: Models, Ab Initio Methods and Supercomputing, edited by Stefan Blügel, Nicole Helbig, Volker Meden, and Daniel Wortmann, 74:A4.1-A4.21. Key Technologies. Jülich: Forschungszentrum Jülich, 2014.' ieee: 'C. Friedrich and A. Schindlmayr, “Many-body perturbation theory: The GW approximation,” in Computing Solids: Models, ab initio Methods and Supercomputing, vol. 74, S. Blügel, N. Helbig, V. Meden, and D. Wortmann, Eds. Jülich: Forschungszentrum Jülich, 2014, p. A4.1-A4.21.' mla: 'Friedrich, Christoph, and Arno Schindlmayr. “Many-Body Perturbation Theory: The GW Approximation.” Computing Solids: Models, Ab Initio Methods and Supercomputing, edited by Stefan Blügel et al., vol. 74, Forschungszentrum Jülich, 2014, p. A4.1-A4.21.' short: 'C. Friedrich, A. Schindlmayr, in: S. Blügel, N. Helbig, V. Meden, D. Wortmann (Eds.), Computing Solids: Models, Ab Initio Methods and Supercomputing, Forschungszentrum Jülich, Jülich, 2014, p. A4.1-A4.21.' conference: end_date: 2014-03-21 location: Jülich name: 45th Spring School of the Institute of Solid State Research start_date: 2014-03-10 date_created: 2020-08-27T21:40:39Z date_updated: 2022-01-06T06:53:35Z ddc: - '530' department: - _id: '296' editor: - first_name: Stefan full_name: Blügel, Stefan last_name: Blügel - first_name: Nicole full_name: Helbig, Nicole last_name: Helbig - first_name: Volker full_name: Meden, Volker last_name: Meden - first_name: Daniel full_name: Wortmann, Daniel last_name: Wortmann file: - access_level: request content_type: application/pdf creator: schindlm date_created: 2020-10-05T10:57:49Z date_updated: 2022-01-06T06:53:34Z description: © 2014 Forschungszentrum Jülich file_id: '19876' file_name: A4-Friedrich.pdf file_size: 718521 relation: main_file title: 'Many-body perturbation theory: The GW approximation' file_date_updated: 2022-01-06T06:53:34Z has_accepted_license: '1' intvolume: ' 74' language: - iso: eng main_file_link: - open_access: '1' url: http://hdl.handle.net/2128/8540 oa: '1' page: A4.1-A4.21 place: Jülich publication: 'Computing Solids: Models, ab initio Methods and Supercomputing' publication_identifier: isbn: - 978-3-89336-912-6 issn: - 1866-1807 publication_status: published publisher: Forschungszentrum Jülich series_title: Key Technologies status: public title: 'Many-body perturbation theory: The GW approximation' type: book_chapter user_id: '458' volume: 74 year: '2014' ... --- _id: '18475' abstract: - lang: eng text: The frequency-dependent dielectric function and the second-order polarizability tensor of ferroelectric LiNbO3 are calculated from first principles. The calculations are based on the electronic structure obtained from density-functional theory. The subsequent application of the GW approximation to account for quasiparticle effects and the solution of the Bethe–Salpeter equation yield a dielectric function for the stoichiometric material that slightly overestimates the absorption onset and the oscillator strength in comparison with experimental measurements. Calculations at the level of the independent-particle approximation indicate that these deficiencies are at least partially related to the neglect of intrinsic defects typical for the congruent material. The second-order polarizability calculated within the independent-particle approximation predicts strong nonlinear coefficients for photon energies above 1.5 eV. The comparison with measured data suggests that self-energy effects improve the agreement between experiment and theory. The intrinsic defects of congruent samples reduce the optical nonlinearities, in particular for the 21 and 31 tensor components, further improving the agreement with measured data. author: - first_name: Arthur full_name: Riefer, Arthur last_name: Riefer - first_name: Martin full_name: Rohrmüller, Martin last_name: Rohrmüller - first_name: Marc full_name: Landmann, Marc last_name: Landmann - first_name: Simone full_name: Sanna, Simone last_name: Sanna - first_name: Eva full_name: Rauls, Eva last_name: Rauls - first_name: Nora Jenny full_name: Vollmers, Nora Jenny last_name: Vollmers - first_name: Rebecca full_name: Hölscher, Rebecca last_name: Hölscher - first_name: Matthias full_name: Witte, Matthias last_name: Witte - first_name: Yanlu full_name: Li, Yanlu last_name: Li - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 citation: ama: 'Riefer A, Rohrmüller M, Landmann M, et al. Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations. In: Nagel WE, Kröner DH, Resch MM, eds. High Performance Computing in Science and Engineering ‘13. Transactions of the High Performance Computing Center, Stuttgart. Cham: Springer; 2013:93-104. doi:10.1007/978-3-319-02165-2_8' apa: 'Riefer, A., Rohrmüller, M., Landmann, M., Sanna, S., Rauls, E., Vollmers, N. J., … Schmidt, W. G. (2013). Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations. In W. E. Nagel, D. H. Kröner, & M. M. Resch (Eds.), High Performance Computing in Science and Engineering ‘13 (pp. 93–104). Cham: Springer. https://doi.org/10.1007/978-3-319-02165-2_8' bibtex: '@inbook{Riefer_Rohrmüller_Landmann_Sanna_Rauls_Vollmers_Hölscher_Witte_Li_Gerstmann_et al._2013, place={Cham}, series={Transactions of the High Performance Computing Center, Stuttgart}, title={Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations}, DOI={10.1007/978-3-319-02165-2_8}, booktitle={High Performance Computing in Science and Engineering ‘13}, publisher={Springer}, author={Riefer, Arthur and Rohrmüller, Martin and Landmann, Marc and Sanna, Simone and Rauls, Eva and Vollmers, Nora Jenny and Hölscher, Rebecca and Witte, Matthias and Li, Yanlu and Gerstmann, Uwe and et al.}, editor={Nagel, Wolfgang E. and Kröner, Dietmar H. and Resch, Michael M.Editors}, year={2013}, pages={93–104}, collection={Transactions of the High Performance Computing Center, Stuttgart} }' chicago: 'Riefer, Arthur, Martin Rohrmüller, Marc Landmann, Simone Sanna, Eva Rauls, Nora Jenny Vollmers, Rebecca Hölscher, et al. “Lithium Niobate Dielectric Function and Second-Order Polarizability Tensor from Massively Parallel Ab Initio Calculations.” In High Performance Computing in Science and Engineering ‘13, edited by Wolfgang E. Nagel, Dietmar H. Kröner, and Michael M. Resch, 93–104. Transactions of the High Performance Computing Center, Stuttgart. Cham: Springer, 2013. https://doi.org/10.1007/978-3-319-02165-2_8.' ieee: 'A. Riefer et al., “Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations,” in High Performance Computing in Science and Engineering ‘13, W. E. Nagel, D. H. Kröner, and M. M. Resch, Eds. Cham: Springer, 2013, pp. 93–104.' mla: Riefer, Arthur, et al. “Lithium Niobate Dielectric Function and Second-Order Polarizability Tensor from Massively Parallel Ab Initio Calculations.” High Performance Computing in Science and Engineering ‘13, edited by Wolfgang E. Nagel et al., Springer, 2013, pp. 93–104, doi:10.1007/978-3-319-02165-2_8. short: 'A. Riefer, M. Rohrmüller, M. Landmann, S. Sanna, E. Rauls, N.J. Vollmers, R. Hölscher, M. Witte, Y. Li, U. Gerstmann, A. Schindlmayr, W.G. Schmidt, in: W.E. Nagel, D.H. Kröner, M.M. Resch (Eds.), High Performance Computing in Science and Engineering ‘13, Springer, Cham, 2013, pp. 93–104.' date_created: 2020-08-27T21:48:43Z date_updated: 2022-01-06T06:53:35Z ddc: - '530' department: - _id: '296' - _id: '295' doi: 10.1007/978-3-319-02165-2_8 editor: - first_name: Wolfgang E. full_name: Nagel, Wolfgang E. last_name: Nagel - first_name: Dietmar H. full_name: Kröner, Dietmar H. last_name: Kröner - first_name: Michael M. full_name: Resch, Michael M. last_name: Resch external_id: isi: - '000360004100009' file: - access_level: closed content_type: application/pdf creator: schindlm date_created: 2020-08-28T15:34:44Z date_updated: 2020-08-30T14:57:36Z description: © 2013 Springer International Publishing, Switzerland file_id: '18586' file_name: Riefer2013_Chapter_LithiumNiobateDielectricFuncti.pdf file_size: 517819 relation: main_file title: Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations file_date_updated: 2020-08-30T14:57:36Z has_accepted_license: '1' isi: '1' language: - iso: eng page: 93-104 place: Cham project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing publication: High Performance Computing in Science and Engineering ‘13 publication_identifier: eisbn: - 978-3-319-02165-2 isbn: - 978-3-319-02164-5 publication_status: published publisher: Springer quality_controlled: '1' series_title: Transactions of the High Performance Computing Center, Stuttgart status: public title: Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations type: book_chapter user_id: '458' year: '2013' ... --- _id: '18476' abstract: - lang: eng text: We investigate the band dispersion and relevant electronic properties of rubrene single crystals within the GW approximation. Due to the self-energy correction, the dispersion of the highest occupied molecular orbital (HOMO) band increases by 0.10 eV compared to the dispersion of the Kohn-Sham eigenvalues within the generalized gradient approximation, and the effective hole mass consequently decreases. The resulting value of 0.90 times the electron rest mass along the Γ-Y direction in the Brillouin zone is closer to experimental measurements than that obtained from density-functional theory. The enhanced bandwidth is explained in terms of the intermolecular hybridization of the HOMO(Y) wave function along the stacking direction of the molecules. Overall, our results support the bandlike interpretation of charge-carrier transport in rubrene. article_number: '115438' article_type: original author: - first_name: Susumu full_name: Yanagisawa, Susumu last_name: Yanagisawa - first_name: Yoshitada full_name: Morikawa, Yoshitada last_name: Morikawa - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Yanagisawa S, Morikawa Y, Schindlmayr A. HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation. Physical Review B. 2013;88(11). doi:10.1103/PhysRevB.88.115438' apa: 'Yanagisawa, S., Morikawa, Y., & Schindlmayr, A. (2013). HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation. Physical Review B, 88(11). https://doi.org/10.1103/PhysRevB.88.115438' bibtex: '@article{Yanagisawa_Morikawa_Schindlmayr_2013, title={HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation}, volume={88}, DOI={10.1103/PhysRevB.88.115438}, number={11115438}, journal={Physical Review B}, publisher={American Physical Society}, author={Yanagisawa, Susumu and Morikawa, Yoshitada and Schindlmayr, Arno}, year={2013} }' chicago: 'Yanagisawa, Susumu, Yoshitada Morikawa, and Arno Schindlmayr. “HOMO Band Dispersion of Crystalline Rubrene: Effects of Self-Energy Corrections within the GW Approximation.” Physical Review B 88, no. 11 (2013). https://doi.org/10.1103/PhysRevB.88.115438.' ieee: 'S. Yanagisawa, Y. Morikawa, and A. Schindlmayr, “HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation,” Physical Review B, vol. 88, no. 11, 2013.' mla: 'Yanagisawa, Susumu, et al. “HOMO Band Dispersion of Crystalline Rubrene: Effects of Self-Energy Corrections within the GW Approximation.” Physical Review B, vol. 88, no. 11, 115438, American Physical Society, 2013, doi:10.1103/PhysRevB.88.115438.' short: S. Yanagisawa, Y. Morikawa, A. Schindlmayr, Physical Review B 88 (2013). date_created: 2020-08-27T21:59:44Z date_updated: 2022-01-06T06:53:36Z ddc: - '530' department: - _id: '296' doi: 10.1103/PhysRevB.88.115438 external_id: isi: - '000325175600010' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-27T22:01:50Z date_updated: 2020-08-30T14:58:43Z description: © 2013 American Physical Society file_id: '18477' file_name: PhysRevB.88.115438.pdf file_size: 4438475 relation: main_file title: 'HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation' file_date_updated: 2020-08-30T14:58:43Z has_accepted_license: '1' intvolume: ' 88' isi: '1' issue: '11' language: - iso: eng oa: '1' publication: Physical Review B publication_identifier: eissn: - 1550-235X issn: - 1098-0121 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: 'HOMO band dispersion of crystalline rubrene: Effects of self-energy corrections within the GW approximation' type: journal_article user_id: '458' volume: 88 year: '2013' ... --- _id: '13525' abstract: - lang: eng text: The frequency-dependent dielectric function and the second-order polarizability tensor of ferroelectric LiNbO3 are calculated from first principles. The calculations are based on the electronic structure obtained from density-functional theory. The subsequent application of the GW approximation to account for quasiparticle effects and the solution of the Bethe-Salpeter equation for the stoichiometric material yield a dielectric function that slightly overestimates the absorption onset and the oscillator strength in comparison with experimental measurements. Calculations at the level of the independent-particle approximation indicate that these deficiencies are, at least, partially related to the neglect of intrinsic defects typical for the congruent material. The second-order polarizability calculated within the independent-particle approximation predicts strong nonlinear coefficients for photon energies above 1.5 eV. The comparison with measured data suggests that the inclusion of self-energy effects in the nonlinear optical response leads to a better agreement with experiments. The intrinsic defects of congruent samples reduce the optical nonlinearities, in particular, for the 21 and 31 tensor components, further improving the agreement between experiments and theory. article_number: '195208' article_type: original author: - first_name: Arthur full_name: Riefer, Arthur last_name: Riefer - first_name: Simone full_name: Sanna, Simone last_name: Sanna - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 citation: ama: Riefer A, Sanna S, Schindlmayr A, Schmidt WG. Optical response of stoichiometric and congruent lithium niobate from first-principles calculations. Physical Review B. 2013;87(19). doi:10.1103/PhysRevB.87.195208 apa: Riefer, A., Sanna, S., Schindlmayr, A., & Schmidt, W. G. (2013). Optical response of stoichiometric and congruent lithium niobate from first-principles calculations. Physical Review B, 87(19). https://doi.org/10.1103/PhysRevB.87.195208 bibtex: '@article{Riefer_Sanna_Schindlmayr_Schmidt_2013, title={Optical response of stoichiometric and congruent lithium niobate from first-principles calculations}, volume={87}, DOI={10.1103/PhysRevB.87.195208}, number={19195208}, journal={Physical Review B}, publisher={American Physical Society}, author={Riefer, Arthur and Sanna, Simone and Schindlmayr, Arno and Schmidt, Wolf Gero}, year={2013} }' chicago: Riefer, Arthur, Simone Sanna, Arno Schindlmayr, and Wolf Gero Schmidt. “Optical Response of Stoichiometric and Congruent Lithium Niobate from First-Principles Calculations.” Physical Review B 87, no. 19 (2013). https://doi.org/10.1103/PhysRevB.87.195208. ieee: A. Riefer, S. Sanna, A. Schindlmayr, and W. G. Schmidt, “Optical response of stoichiometric and congruent lithium niobate from first-principles calculations,” Physical Review B, vol. 87, no. 19, 2013. mla: Riefer, Arthur, et al. “Optical Response of Stoichiometric and Congruent Lithium Niobate from First-Principles Calculations.” Physical Review B, vol. 87, no. 19, 195208, American Physical Society, 2013, doi:10.1103/PhysRevB.87.195208. short: A. Riefer, S. Sanna, A. Schindlmayr, W.G. Schmidt, Physical Review B 87 (2013). date_created: 2019-09-30T14:11:18Z date_updated: 2022-01-06T06:51:38Z ddc: - '530' department: - _id: '295' - _id: '296' doi: 10.1103/PhysRevB.87.195208 external_id: isi: - '000319391000002' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-27T22:06:46Z date_updated: 2020-08-30T14:53:40Z description: © 2013 American Physical Society file_id: '18478' file_name: PhysRevB.87.195208.pdf file_size: 791961 relation: main_file title: Optical response of stoichiometric and congruent lithium niobate from first-principles calculations file_date_updated: 2020-08-30T14:53:40Z has_accepted_license: '1' intvolume: ' 87' isi: '1' issue: '19' language: - iso: eng oa: '1' project: - _id: '52' name: Computing Resources Provided by the Paderborn Center for Parallel Computing publication: Physical Review B publication_identifier: eissn: - 1550-235X issn: - 1098-0121 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: Optical response of stoichiometric and congruent lithium niobate from first-principles calculations type: journal_article user_id: '458' volume: 87 year: '2013' ... --- _id: '18479' abstract: - lang: eng text: The GW approximation for the electronic self-energy is an important tool for the quantitative prediction of excited states in solids, but its mathematical exploration is hampered by the fact that it must, in general, be evaluated numerically even for very simple systems. In this paper I describe a nontrivial model consisting of two electrons on the surface of a sphere, interacting with the normal long-range Coulomb potential, and show that the GW self-energy, in the absence of self-consistency, can in fact be derived completely analytically in this case. The resulting expression is subsequently used to analyze the convergence of the energy gap between the highest occupied and the lowest unoccupied quasiparticle orbital with respect to the total number of states included in the spectral summations. The asymptotic formula for the truncation error obtained in this way, whose dominant contribution is proportional to the cutoff energy to the power −3/2, may be adapted to extrapolate energy gaps in other systems. article_number: '075104' article_type: original author: - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: Schindlmayr A. Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere. Physical Review B. 2013;87(7). doi:10.1103/PhysRevB.87.075104 apa: Schindlmayr, A. (2013). Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere. Physical Review B, 87(7), Article 075104. https://doi.org/10.1103/PhysRevB.87.075104 bibtex: '@article{Schindlmayr_2013, title={Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere}, volume={87}, DOI={10.1103/PhysRevB.87.075104}, number={7075104}, journal={Physical Review B}, publisher={American Physical Society}, author={Schindlmayr, Arno}, year={2013} }' chicago: Schindlmayr, Arno. “Analytic Evaluation of the Electronic Self-Energy in the GW Approximation for Two Electrons on a Sphere.” Physical Review B 87, no. 7 (2013). https://doi.org/10.1103/PhysRevB.87.075104. ieee: 'A. Schindlmayr, “Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere,” Physical Review B, vol. 87, no. 7, Art. no. 075104, 2013, doi: 10.1103/PhysRevB.87.075104.' mla: Schindlmayr, Arno. “Analytic Evaluation of the Electronic Self-Energy in the GW Approximation for Two Electrons on a Sphere.” Physical Review B, vol. 87, no. 7, 075104, American Physical Society, 2013, doi:10.1103/PhysRevB.87.075104. short: A. Schindlmayr, Physical Review B 87 (2013). date_created: 2020-08-27T22:09:04Z date_updated: 2022-11-11T06:41:32Z ddc: - '530' department: - _id: '296' doi: 10.1103/PhysRevB.87.075104 external_id: arxiv: - '1302.6368' isi: - '000314682500002' file: - access_level: open_access content_type: application/pdf creator: schindlm date_created: 2020-08-28T10:01:56Z date_updated: 2020-08-30T14:54:49Z description: © 2013 American Physical Society file_id: '18541' file_name: PhysRevB.87.075104.pdf file_size: 229196 relation: main_file title: Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere file_date_updated: 2020-08-30T14:54:49Z has_accepted_license: '1' intvolume: ' 87' isi: '1' issue: '7' language: - iso: eng oa: '1' publication: Physical Review B publication_identifier: eissn: - 1550-235X issn: - 1098-0121 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: Analytic evaluation of the electronic self-energy in the GW approximation for two electrons on a sphere type: journal_article user_id: '458' volume: 87 year: '2013' ...