Theory of binary alloys of different constituent bandwidths

A selfconsistent single site effective Hamiltonian is derived within the multiple scattering theory to describe a disordered tight binding binary alloy for which both constituent bandwidths and site potentials are different. The total density of states and the constituent partial density of states are calculated and discussed. It is shown that the multiple scattering approach provides a suitable formalism for investigating problems such as (i) the extension of the Koster-Slater formula when impurity and host have different bandwidths, (ii) the appearance of a satellite-peak structure in the broader bandwidth component density of states when the difference in bandwidths is great enough, (iii) the generalization of the theory to a two band model relevant for transition and noble metal alloys.