Coherent-potential approximation in the tight-binding linear muffin-tin orbital method.

Abstract

We describe a consistent approach for applying the coherent-potential approximation (CPA) to the various representations of the linear muffin-tin orbital method. Unlike the previous works of Kudrnovsk\'y et al. [Phys. Rev. B 35, 2487 (1987); 41, 7515 (1990)], our results for the ensemble-averaged Green functions in the tight-binding representation yield E- and r-dependent quantities that are consistent with the traditional applications of the single-site CPA. To illustrate the reliability and the usefulness of our approach we compare the nonspherically averaged charge densities, calculated in real space, of ordered NiPt in L${1}_{0}$ structure and the substitutionally disordered ${\mathrm{Ni}}_{0.5}$${\mathrm{Pt}}_{0.5}$ on a face-centered-cubic lattice.