Localized-orbital description of wave functions and energy bands in semiconductors

Bloch sums constructed of s-, p-, and d-symmetry localized orbitals are used as basis sets for describing the pseudo-wave functions and energy bands of Si, Ge, and GaAs. For a simple four-state-per-atom s-p basis set of Slater orbitals, accurate valence and conduction bands are obtained by adjusting the exponential decay constant of the orbitals. With a ten-state-per-atom basis, accurate charge densities and energy bands are calculated using a variational approach.