Structural model for pseudobinary semiconductor alloys

Using the Keating valence-force-field model with large periodic supercells, we analyze the structural relaxations of pseudobinary III-V and II-VI semiconductor alloys. We quantitatively predict the dependence of bond lengths and second-neighbor distances on alloy composition, and show that the multimodal distributions of second-neighbor distances may be explained in terms of a simple set of local geometries. Intrinsic alloy broadening of bond-length distributions is also calculated and compared with experimentally measured values.