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Born Effective Charges of Barium Titanate: band by band decomposition and sensitivity to structural features

Ph. Ghosez·X. Gonze·Ph. Lambin·J. -P. Michenaud
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Abstract

The Born effective charge tensors of Barium Titanate have been calculated for each of its 4 phases. Large effective charges of Ti and O, also predicted by shell model calculations and made plausible by a simplified model, reflect the partial 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.

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Ph. Ghosez, X. Gonze, Ph. Lambin, J. -P. Michenaud. 1994-12-02. Born Effective Charges of Barium Titanate: band by band decomposition and sensitivity to structural features. https://doi.org/10.1103/physrevb.51.6765

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