Fast Korringa-Kohn-Rostoker coherent potential approximation and its application to FCC Ni-Fe systems

A fast KKR CPA method is explained and its convergence properties are examined numerically. It is shown that a step number of N ≃ 300, which determines the number of k-points used for the numerical integration in the k-space as well as the number of iteration steps in determining the coherent t-matrix, is sufficient for most purposes, including total-energy calculations. As a typical application the electronic structure of ferromagnetic Ni-Fe systems is calculated in the framework of the KKR CPA combined with the local spin density approximation, which demonstrates the feasibility of the present method.