Application of a Kohn-Sham-like formulation of the self-consistent atomic deformation model

Abstract

The self-consistent atomic deformation model is applied to compounds selected to illustrate two important features of the model: 1) The formulation of the potential from a Kohn-Sham like variational treatment of the total energy produces atomic energy levels which obey Janak's theorem. This feature is illustrated by results for LaSrCuO₄ with the ions constrained to be spherical. 2) The importance of non-spherical distortions of oxygen ions in ferroelectric oxides is demonstrated with results for BaTiO₃ and KNbO₃. Born effective charges are computed and compared with previous calculations for these compounds and the alkaline earth oxides.

Key Words:

• Density functional theory
• polarization
• electronic structure
• electron gas
• ab initio calculation
• ferroelectricity