  We analyze and present applications of a recently proposed empirical
tight-binding scheme for investigating the effects of alloy disorder on various
electronic and optical properties of semiconductor alloys, such as the band gap
variation, the localization of charge carriers, and the optical transitions.
The results for a typical antimony-containing III-V alloy, GaAsSb, show that
the new scheme greatly improves the accuracy in reproducing the experimental
alloy band gaps compared to other widely used schemes. The atomistic nature of
the empirical tight-binding approach paired with a reliable parameterization
enables more detailed physical insights into the effects of disorder in alloyed
materials.
