One-particle properties of compositionally modulated alloys in the coherent potential approximation

We propose a simple generalization of the original single-site coherent potential approximation (CPA) applicable to compositionally modulated alloys. Although the original single-site CPA gives an almost structureless density of states, we find that for strong modulation and relatively strong scattering our generalization of the CPA yields densities of states which exhibit considerable structure and which represent the exact densities of states remarkably well. In this sense our generalization is more accurate than the original CPA from which it was obtained.