APPLICATION OF A KOHN-SHAM-LIKE FORMULATION OF THE SELF-CONSISTENT ATOMIC DEFORMATION MODEL

The self-consistent atomic deformation model is applied to compounds s elected to illustrate two important features of the model: 1) The form ulation of the potential from a Kohn-Sham like variational treatment o f the total energy produces atomic energy levels which obey Janak's th eorem. This feature is illustrated by results for LaSrCuO4 with the io ns constrained to be spherical. 2) The importance of non-spherical dis tortions of oxygen ions in ferroelectric oxides is demonstrated with r esults for BaTiO3 and KNbO3. Born effective charges are computed and c ompared with previous calculations for these compounds and the alkalin e earth oxides.