Theory of alloys, a coherent pseudopotential model

The authors present a model for predicting the properties of a random alloy A x B y . A method is developed for finding an effective energy dependent potential, localized on a single site in the Wannier representation, to describe the effect of a B atom in an A host. A multiple scattering theory is then used to calculate the effect of many impurities, the model for this part of the calculation involving an iteration procedure which tends to the same solution of the formal problem as the 'coherent potential approximation' (CPA) of Soven and others. The most important feature of the calculation is that the input data are the density of states for both a pure A and a pure B crystal so that the model can be used easily for real physical systems whose densities of states are known; no other adjustable parameters are involved in this theory. The method is applied to the case of a silver-gold alloy and results are obtained for the specific heat and resistivity which compare favourably with experimental results.