Electronic and Polar Properties of Vanadate Compounds Stabilized by Epitaxial Strain
Recent experimental and computational studies have demonstrated pressure and epitaxial stabilization of polar PbVO3 phases with perovskite-derivative crystal structures. In this study, we demonstrate, by density functional theory (DFT) calculations, the stability of similar perovskite-derivative structures in the KVO3 and NaVO3 systems when subjected to compressive biaxial strain. The electronic structure and polar properties of these compounds are computed as a function of biaxial strain, and the results are compared to those obtained for experimentally observed PbVO3 structures. It is demonstrated that the substitution of Pb with monovalent K or Na cations increases the strength of the vanadyl bond due to the removal of the spatially extended Pb 6p states. Both KVO3 and NaVO3 exhibit epitaxially stabilized perovskite-derivative phases having large polarizations and only small total energy increases relative to their unstrained bulk structures. The calculated epitaxial phase diagram for KVO3 predicts a strain-energy driving force for a phase separation from ~% to 1.5% misfit strain into a polar Cm phase, having square-pyramidal coordination of the B-site, and a paraelectric Pbcm phase, having tetrahedral coordination of the B-site. The results show that strain-stabilized polar vanadate compounds may occur for other compositions in addition to PbVO3 and that changes in the A-site species can be used to tune bonding, structure, and functional properties in these systems.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1478353
- Journal Information:
- Chemistry of Materials, Vol. 30, Issue 17; ISSN 0897-4756
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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