Temperature dependence of energy gaps in some II–VI compounds

The Brooks-Yu theory is applied to the calculation of the temperature dependence of the energy band gaps in some II–VI compounds. The theory is applied in the framework of the empirical pseudo-potential method, and utilizes a recent lattice dynamical calculation of the Debye-Waller factors. The temperature dependence of several critical-point band gaps are determined and compared with a vailable experimental data. In general, reasonable agreement is obtained. The interesting case of HgTe, which exhibits an anomalous positive temperature coefficient of the fundamental band gap, is also discussed.