SPECIAL QUASIRANDOM STRUCTURES

Structural models used in calculations of properties of substitutionally random A1-xBx alloys are usually constructed by randomly occupying each of the N sites of a periodic cell by A or B. We show that it is possible to design special quasirandom structures (SQSs) that mimic for small N (even N=8) the first few, physically most relevant radial correlation functions of a perfectly random structure far better than the standard technique does. We demonstrate the usefulness of these SQSs by calculating optical and thermodynamic properties of a number of semiconductor alloys in the local-density formalism. © 1990 The American Physical Society.