Erhart, Paul ; Klein, Andreas ; Åberg, Daniel ; Sadigh, Babak (2022)
Efficacy of the DFT + U formalism for modeling hole polarons in perovskite oxides.
In: Physical Review B, 2014, 90 (3)
doi: 10.26083/tuprints-00021157
Artikel, Zweitveröffentlichung, Verlagsversion
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Kurzbeschreibung (Abstract)
We investigate the formation of self-trapped holes (STH) in three prototypical perovskites (SrTiO₃, BaTiO₃, PbTiO₃) using a combination of density functional theory (DFT) calculations with local potentials and hybrid functionals. First we construct a local correction potential for polaronic configurations in SrTiO₃ that is applied via the DFT + U method and matches the forces from hybrid calculations. We then use the DFT + U potential to search the configuration space and locate the lowest energy STH configuration. It is demonstrated that both the DFT + U potential and the hybrid functional yield a piecewise linear dependence of the total energy on the occupation of the STH level, suggesting that self-interaction effects have been properly removed. The DFT + U model is found to be transferable to BaTiO₃ and PbTiO₃, and STH formation energies from DFT + U and hybrid calculations are in close agreement for all three materials. STH formation is found to be energetically favorable in SrTiO₃ and BaTiO₃ but not in PbTiO₃, which can be rationalized by considering the alignment of the valence band edges on an absolute energy scale. In the case of PbTiO₃ the strong coupling between Pb 6s and O 2p states lifts the valence band minimum (VBM) compared to SrTiO₃ and BaTiO₃. This reduces the separation between VBM and STH level and renders the STH configuration metastable with respect to delocalization (band hole state). We expect that the present approach can be adapted to study STH formation also in oxides with different crystal structures and chemical compositions.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2022 |
| Autor(en): | Erhart, Paul ; Klein, Andreas ; Åberg, Daniel ; Sadigh, Babak |
| Art des Eintrags: | Zweitveröffentlichung |
| Titel: | Efficacy of the DFT + U formalism for modeling hole polarons in perovskite oxides |
| Sprache: | Englisch |
| Publikationsjahr: | 2022 |
| Publikationsdatum der Erstveröffentlichung: | 2014 |
| Verlag: | American Physical Society |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Physical Review B |
| Jahrgang/Volume einer Zeitschrift: | 90 |
| (Heft-)Nummer: | 3 |
| Kollation: | 8 Seiten |
| DOI: | 10.26083/tuprints-00021157 |
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/21157 |
| Zugehörige Links: | |
| Herkunft: | Zweitveröffentlichungsservice |
| Kurzbeschreibung (Abstract): | We investigate the formation of self-trapped holes (STH) in three prototypical perovskites (SrTiO₃, BaTiO₃, PbTiO₃) using a combination of density functional theory (DFT) calculations with local potentials and hybrid functionals. First we construct a local correction potential for polaronic configurations in SrTiO₃ that is applied via the DFT + U method and matches the forces from hybrid calculations. We then use the DFT + U potential to search the configuration space and locate the lowest energy STH configuration. It is demonstrated that both the DFT + U potential and the hybrid functional yield a piecewise linear dependence of the total energy on the occupation of the STH level, suggesting that self-interaction effects have been properly removed. The DFT + U model is found to be transferable to BaTiO₃ and PbTiO₃, and STH formation energies from DFT + U and hybrid calculations are in close agreement for all three materials. STH formation is found to be energetically favorable in SrTiO₃ and BaTiO₃ but not in PbTiO₃, which can be rationalized by considering the alignment of the valence band edges on an absolute energy scale. In the case of PbTiO₃ the strong coupling between Pb 6s and O 2p states lifts the valence band minimum (VBM) compared to SrTiO₃ and BaTiO₃. This reduces the separation between VBM and STH level and renders the STH configuration metastable with respect to delocalization (band hole state). We expect that the present approach can be adapted to study STH formation also in oxides with different crystal structures and chemical compositions. |
| Status: | Verlagsversion |
| URN: | urn:nbn:de:tuda-tuprints-211579 |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 530 Physik 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Oberflächenforschung DFG-Sonderforschungsbereiche (inkl. Transregio) DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 595: Elektrische Ermüdung DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 595: Elektrische Ermüdung > B - Charakterisierung DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 595: Elektrische Ermüdung > B - Charakterisierung > Teilprojekt B7:Polarisation und Ladung in elektrisch ermüdeten Ferroelektrika |
| Hinterlegungsdatum: | 19 Apr 2022 13:37 |
| Letzte Änderung: | 20 Apr 2022 05:15 |
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- Efficacy of the DFT + U formalism for modeling hole polarons in perovskite oxides. (deposited 19 Apr 2022 13:37) [Gegenwärtig angezeigt]
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