Electronic theory of phase stability in substitutional alloys: The generalized perturbation method versus the Connolly-Williams method

A detailed analysis of the tendencies toward ordering and phase separation, and more generally the stability properties at T≠0 K in substitutional alloys, is carried out using the prescription proposed by Connolly and Williams and the generalized perturbation method. Both methods are examined and contrasted within the framework of a simple but realistic tight-binding model applicable to paramagnetic transition-metal alloys