Investigation of band inversion in (Pb,Sn)Te alloys using ab initio calculations

The electronic structure of the (Pb,Sn)Te alloy displays the so-called "band inversion" between its two end members, PbTe and SnTe. Although the electronic structures of these two end members have been extensively studied by first-principles calculations, there have been no reports of first-principles calculations of the evolution of the band gap with composition. We have studied systematically the band structure using first-principles calculations within the generalized gradient approximation and have investigated the effects of compositional disorder. By taking into account local disorder, we show that the calculated dependence of band gap on composition is in good agreement with experimental results.