Electronic structure ofHg1−xCdxTe

The effects of alloy disorder on the electronic structure of ${\mathrm{Hg}}_{1-x}{\mathrm{Cd}}_x\mathrm{Te}$ are examined with the use of the coherent-potential approximation. An empirical tight-binding scheme, including spin-orbit effects, is employed. The choice of parameters is given special emphasis. A new HgTe band structure is obtained. Alloying effects are illustrated by quasiparticle spectral densities, total and projected densities of states, and self-energy corrections to the virtual-crystal energy bands. Strong cation $s$ scattering results in significant damping far from the band edges and accounts for the split-band behavior seen in photoemission experiments. The unusual bowing effects of the fundamental band gap and that associated with the $E_1$ transition are well explained. The weak scattering regime is shown to apply near the band edges. The electron mobility due to alloy scattering is large and does not appear to limit the observed magnitude.