Self-consistent Green’s-function method for surfaces of random alloys

An efficient self-consistent Green’s-function technique using a generalization of the coherent-potential approximation method is presented in order to describe the electronic structure of inhomogeneous semi-infinite alloys with varying concentration profiles at the surface within the local-density approximation. The formalism is applied to the study of the electronic properties of the (001) surface of ${\mathrm{Cu}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Ni}}_{\mathit{x}}$ fcc random alloys.