Electronic Structure ofHg1−xCdxTeAlloys and Charge-Density Calculations Using RepresentativekPoints

Abstract

We have calculated the electronic band structures and charge densities near $\Gamma$ for the ${\mathrm{Hg}}_{1-x}{\mathrm{Cd}}_x\mathrm{Te}$ alloy system using the empirical-pseudopotential method. We find that the energy gap varies linearly with $x$, with the semimetal-semiconductor transition occurring at $x=0.165\mathrm{}$. We have calculated the total electronic charge densities of HgTe and CdTe by using a weighted sum of the charge densities at a few symmetry points in the Brillouin zone and for the nonsymmetry point used by Baldereschi. We show that for a large class of semiconducting compounds the total electronic charge density can be obtained to a very high degree of accuracy using these representative $k$ points.