Cluster densities of states of nonrandom substitutionally disordered alloys

The embedded-cluster method is used to calculate the density of states (DOS) of nonrandom substitutionally disordered alloys. This method is based on the calculation of the Green's function for a cluster of atoms embedded in an effective medium. The effect of increasing cluster size as well as of different choices of the effective medium is investigated numerically in terms of one-dimensional alloys with various scattering strengths and degrees of short-range-order (SRO). A method for the self-consistent treatment of SRO in terms of the pair distribution function is proposed and in many cases is found to lead to results in much better agreement with exact DOS's than those obtained when SRO is not treated self-consistently.