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Prediction of possible CaMnO 3 modifications using an ab initio minimization data‐mining approach
Author(s) -
Zagorac Jelena,
Zagorac Dejan,
Zarubica Aleksandra,
Schön J. Christian,
Djuris Katarina,
Matovic Branko
Publication year - 2014
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520614013122
Subject(s) - orthorhombic crystal system , octahedron , ab initio , perovskite (structure) , density functional theory , type (biology) , materials science , phase transition , phase (matter) , crystal structure , crystallography , physics , condensed matter physics , computational chemistry , chemistry , geology , quantum mechanics , paleontology
We have performed a crystal structure prediction study of CaMnO 3 focusing on structures generated by octahedral tilting according to group–subgroup relations from the ideal perovskite type (), which is the aristotype of the experimentally known CaMnO 3 compound in the Pnma space group. Furthermore, additional structure candidates have been obtained using data mining. For each of the structure candidates, a local optimization on the ab initio level using density‐functional theory (LDA, hybrid B3LYP) and the Hartree‐–Fock (HF) method was performed, and we find that several of the modifications may be experimentally accessible. In the high‐pressure regime, we identify a post‐perovskite phase in the CaIrO 3 type, not previously observed in CaMnO 3 . Similarly, calculations at effective negative pressure predict a phase transition from the orthorhombic perovskite to an ilmenite‐type (FeTiO 3 ) modification of CaMnO 3 .