Born effective charges of barium titanate: Band-by-band decomposition and sensitivity to structural features
- 1 March 1995
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 51 (10), 6765-6768
- https://doi.org/10.1103/physrevb.51.6765
Abstract
The Born effective charge tensors of barium titanate have been calculated for each of its four phases. Large effective charges of Ti and O, also predicted by shell-model calculations and made plausible by a simplified model, reflect the partly covalent character of the chemical bond. A band-by-band decomposition confirms that orbital hybridization is not restricted to Ti and O atoms but also involves Ba, which appears more covalent than generally assumed. Our calculations reveal a strong dependence of the effective charges on the atomic positions contrasting with a relative insensitivity on isotropic volume changes.Keywords
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