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

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.

12 pages Latex, plus 2 Postscript figures

Cited by in corpus (10)

• Spontaneous polarization and piezoelectric constants of III-V nitrides
• The physics of dynamical atomic charges: the case of ABO3 compounds
• Strain-induced ferroelectricity in simple rocksalt binary oxides
• Accurate polarization within a unified Wannier function formalism
• Maximally-localized Wannier Functions in Antiferromagnetic MnO within the FLAPW Formalism
• Band-by-band decomposition of the Born effective charges
• Ab initio Hartree-Fock Born effective charges of LiH, LiF, LiCl, NaF, and NaCl
• Approximate formula for the macroscopic polarization including quantum fluctuations
• Surface Screening Charge and Effective Charge
• Consistency between the Green-Kubo formula and Lorentz model for predicting the infrared dielectric function of polar materials