Influence of local fluctuations of concentration on the electronic density of states in disordered binary alloys

Abstract

The authors present a method which improves the results of the coherent potential approximation (CPA) generally used to study the electronic properties of disordered alloys. They replace the disordered medium by an effective one characterized by a local coherent potential which varies from place to place and depends on the particular alloy configuration. The local electronic density of states is determined by equations similar to that found in the CPA, and then conveniently averaged over all the possible configurations in order to obtain the alloy density of states. As opposed to the CPA, this method yields tails in the allowed energy bands. As an illustration for the method, the authors calculate the electronic density of states of a simple one-dimensional model and compare it to the exact density of states and to the results of CPA calculation.