Effect of Disorder on the Conduction-Band Effective Mass, Valence-Band Spin-Orbit Splitting, and the Direct Band Gap in III-V Alloys

The conduction-band effective mass in small-band-gap III-V alloys has been observed to be heavier than would be expected from a standard $\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}\ifmmode\cdot\else\textperiodcentered\fi{}\stackrel{\ensuremath{\rightarrow}}{\mathrm{p}}$ calculation in the virtual-crystal approximation. Here we analyze the effect of disorder-induced valence-conduction band mixing on this effective mass. It is found that with a consistent set of assumptions for interband and intraband mixing, one can account for the variation of the band gap, the spin-orbit splitting, and the conduction-band mass in these alloys.