Bulk vacancies in CdxHg1–xTe

We report the first theoretical study of vacancies in CdxHg1–xTe alloys. The study employs the tight-binding method for obtaining the Hamiltonian. The Slater–Koster Green's function method is used to obtain the electronic states that result from removing a cation or anion from the virtual crystal used to model the alloys. The primary results are that the anion vacancy levels are far into the conduction band and hence are not likely to produce levels in the gap. In contrast, the cation vacancy is found to produce levels near the valence band edge. We find that spatially these states are very localized on the atoms nearest the vacancy.