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Jahn-Teller distortion, octahedra rotations and orbital ordering in perovskites: KScF 3 as a model system.
Pascale, F; D'Arco, P; Lebègue, S; Dovesi, R.
Afiliação
  • Pascale F; Université de Lorraine-Nancy, CNRS, LEMTA, Nancy, France.
  • D'Arco P; Sorbonne Université, CNRS-INSU, Institut des Sciences de la Terre, ISTeP UMR 7193, Paris, France.
  • Lebègue S; Université de Lorraine-Nancy, CNRS, LPCT, UMR 7019, Nancy, France.
  • Dovesi R; Accademia Delle Science di Torino, Torino, Italy.
J Comput Chem ; 45(14): 1067-1077, 2024 May 30.
Article em En | MEDLINE | ID: mdl-38217380
ABSTRACT
The KScF 3 perovskite has been used as a model for investigating the relative importance of the Jahn-Teller (JT) lift of degeneracy, the ScF 6 octahedra rotation (OR), and the quadrupole-quadrupole interaction linked to different occupancy of the Sc t 2 g subshell in various sites of the unit cell (orbital ordering, OO). The group-subgroup sequence P m 3 ¯ m , P 4 m m m , P 4 m b m , and P n m a , supplemented by C m m m and I 4 m c m , has been explored by using an all electron Gaussian type basis set, hybrid functionals, and the CRYSTAL17 code. The JT lift of degeneracy provides a stabilization about 5 times larger than the sum of the OO and OR effects. The energy gained in the transition from P 4 m m m to P 4 m b m , consisting in a rotation of the octahedra around the c axis, is 1077 µ E h . From P 4 m b m to P n m a , additional rotations around the a and b axes are possible, and the d Sc electron can occupy a different t 2 g orbital, with a total energy reduction of 2318 µ E h . The rotation of the octahedra reduces the strength of superexchange in going from P 4 m m m to P n m a the G-AFM stabilization with respect to FM shrinks by a factor 4.
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Texto completo: 1 Base de dados: MEDLINE Tipo de estudo: Prognostic_studies Idioma: En Ano de publicação: 2024 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Tipo de estudo: Prognostic_studies Idioma: En Ano de publicação: 2024 Tipo de documento: Article