Optical absorption in Hg Te

Optical absorption in intrinsic HgTe is measured in the wavelength range 2.0 to 25 μm at tem peratures from 10 to 295 K. The Γ6 Γ8 transitions are observed at low temperatures. The ab‐ sorption coefficient is theoretically calculated using Kane's formulae for inverted band structure. The results of the calculations based both on the complete Kane theory and on the approximation of large spin‐orbit splitting are obtained. It is shown that the latter approximation does not describe well experimental absorption data. The agreement between the experimental results and the theoretical curves which are based on the complete Kane theory with the reasonable values of band structure parameters is much better. However, for energies greater than 0.35 eV small discrepancy is observed. This discrepancy increases with the energy.