Electronic structure of disordered alloys: Korringa-Kohn-Rostoker cluster coherent-potential approximation

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Abstract
A self-consistent cluster theory, the Korringa-Kohn-Rostoker cluster coherent-potential approximation (KKR-CCPA), is presented to study the electronic structure of the random, substitutionally disordered metallic alloys. This theory combines the augmented-space formalism and conventional Korringa-Kohn-Rostoker methods to determine the effective medium self-consistently. One advantage of this method is that it preserves Herglotz properties of the configuration-averaged Green’s function needed to calculate various electronic properties, such as charge densities, essential for full charge self-consistency. Unlike the single-site approximations, the KKR-CCPA introduces diagonal as well as off-diagonal corrections in the scattering matrices. The formulation has been applied to a model one-dimensional alloy. We find that the density of states in the KKR-CCPA is somewhat structured, due to correlated scattering from clusters of atoms.