ELECTRONIC-STRUCTURE OF RANDOM ALLOYS BY THE LINEAR BAND-STRUCTURE METHODS

We present a new method for the determination of the electronic structure of random transition-metal alloys, which combines the simplicity of empirical tight-binding schemes with the accuracy of the first-principles treatments. Our method uses the first-principles tight-binding linear muffin-tin orbitals description of the electronic states and the coherent-potential approximation to describe the effect of disorder. The central result of our theory is the expression for the configurationally averaged Greenes-function matrix, which is then used to evaluate various one-electron properties of random alloys. The separation of structural and atom-dependent features in our theory allows us to include properly the effect of different positions, widths, and shapes of the band structures of individual alloy constituents. Our theory includes the charge self-consistency and lattice-relaxation effects in an approximate, yet accurate way and it represents a simple alternative to the fully self-consistent treatment. © 1990 The American Physical Society.