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Non-Nominal Value of the Dynamical Effective Charge in Alkaline-Earth Oxides

M. Posternak·A. Baldereschi·H. Krakauer·R. Resta
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Abstract

We calculate ab-initio the electronic states and the Born dynamical charge Z* of the alkaline-earth oxides in the local-density approximation. We investigate the trend of increasing Z* values through the series, using band-by-band decompositions and computational experiments performed on fake materials with artificially-modified covalence. The deviations of Z* from the nominal value 2 are due to the increasing interaction between O 2p orbitals and unoccupied cation d states. We also explain the variations, along the series, of the individual contributions to Z* arising from the occupied band manifolds.

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M. Posternak, A. Baldereschi, H. Krakauer, R. Resta. 1997-02-10. Non-Nominal Value of the Dynamical Effective Charge in Alkaline-Earth Oxides. https://doi.org/10.1103/physrevb.55.r15983

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