Covalent dependence of octahedral rotations in orthorhombic perovskite oxides

Antonio Cammarata*, James M Rondinelli

*Corresponding author for this work

Research output: Contribution to journalArticle

41 Scopus citations

Abstract

The compositional dependence of metal-oxygen BO6octahedral distortions, including bond elongations and rotations, is frequently discussed in the ABO3perovskite literature; structural distortions alleviate internal stresses driven by under- or over-coordinated bond environments. Here we identify the dependence of octahedral rotations from changes in metal-oxygen bond covalency in orthorhombic perovskites. Using density functional theory we formulate a covalency metric, which captures both the real and k-space interactions between the magnitude and sense, i.e., in-phase or out-of-phase, octahedral rotations, to explore the link between the ionic-covalent Fe-O bond and the interoctahedral Fe-O-Fe bond angles in Pbnm ferrates. Our survey finds that the covalency of the metal-oxygen bond is correlated with the rotation amplitude: We find the more covalent the Fe-O bond, the less distorted is the structure and the more important the long-range inter-octahedral (Fe-O-Fe bond angle) interactions. Finally, we show how to indirectly tune the B-O bond covalency by A-cation induced BO6rotations independent of ionic size, facilitating design of targeted bonding interactions in complex perovskites.

Original languageEnglish (US)
Article number114704
JournalJournal of Chemical Physics
Volume141
Issue number11
DOIs
StatePublished - Jan 1 2014

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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