Thomas‐Fermi Approximation for the Valence Electron Densities in Cubic Semiconductors and Insulators

Abstract
The validity of the Thomas‐Fermi approximation for the calculation of valence charge densities in cubic semiconductors and insulators is investigated. Starting from local soft‐core pseudopotentials the valence charge densities are calculated via full band structure calculations and by using the Thomas‐Fermi approach. The results obtained by the two different methods agree surprisingly well. It is found that the validity of the Thomas‐Fermi approximation decreases with increasing ionicity and covalency of the considered compounds.