First-Principles Calculation of Semiconductor-Alloy Phase Diagrams

Combining first-principles self-consistent local-density total-energy calculations with the cluster variation method, we calculate the phase diagram of a semiconductor alloy. It is demonstrated that inclusion of both elastic and chemical interactions in the total-energy functional leads to new features, including the appearance in the same phase diagram of ordering and phase separation, and strain stabilization of both stable and metastable ordered phases.