Extension of the coherent potential approximation for disordered alloys with random transfer integrals

Abstract

AbstractThe one‐electron Hamiltonian which takes into account the diagonal and off‐diagonal randomness is used to describe disordered binary alloys. The k‐dependent self‐energy is calculated in an extended single‐site coherent potential approximation based on the cluster concept. The behaviour is found to be correct in the dilute alloy limit. The formalism is quite tractable for numerical calculations and yields continuous self‐energies. The difference to the method proposed by Brouers is demonstrated by a numerical example.