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Efficacy of the DFT + U formalism for modeling hole polarons in perovskite oxides

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

WarnungEs ist eine neuere Version dieses Eintrags verfügbar.

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
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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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