THE COHERENT-POTENTIAL APPROXIMATION IN THE TIGHT-BINDING LINEARIZED-MUFFIN-TIN-ORBITAL FORMALISM FOR A SINGLE-BAND MODEL OF A SOLID

We have developed a model of a random alloy based on a simplified sing le-(s-type-)band model of a solid introduced by Andersen to demonstrat e the screening of orbitals in the LMTO formalism. To this model we ha ve applied the coherent-potential approximation in the LMTOS put forwa rd by Kudrnovsky et al. The electronic densities of states calculated showed interesting features similar to those found in realistic calcul ations, for all types of disorder considered, namely purely diagonal, both diagonal and off-diagonal, and purely off-diagonal.