Electronic structure of Pb1-xSnxTe semiconductor alloys.

Abstract

The electronic structures of the pseudobinary alloy semiconductors ${\mathrm{Pb}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Sn}}_{\mathrm{x}}$Te are analyzed using a tight-binding model with spin-orbit interaction. The densities of states and the band gaps at the L point are computed for both the effective media using the virtual-crystal approximation and the realistic media employing the recursion method, and the results are compared. Both theories exhibit alloying effects such as band broadening, energy shifts, and Dimmock's band-crossing phenomenon. However, significant deviations from the virtual-crystal approximation are found for the cation-derived s-like deep valence-band states.