Acceptor Resonances in Hg 1 − x Cd x Te

Invoking some gross features of the band structure, we show that the resonance energy in the mixed crystal ${\mathrm{Hg}}_{1\ensuremath{-}x}{\mathrm{Cd}}_{x}\mathrm{Te}$ as a zero-gap semiconductor should increase continuously as the molar fraction of CdTe increases. The increase becomes very strong near the point where an energy gap begins to open up in the alloy. This prediction is in qualitative agreement with experiments. We also give comments on two different models for explaining some observed conductivity anomalies.