Low-frequency optical spectra of lattice vibrations of the Hg1-xZnxTe alloy

The paper reports on assignment of lattice reflection spectra of the Hg1-xZnxTe alloys (x = 0.10, 0.35, and 0.55) measured in the 40-300-K temperature interval and on a comparative analysis of the lattice vibration parameters for two alloy systems, HgZnTe and HgCdTe, in the low-frequency optical vibration region (the region of the anomalous Hg-Te vibrational mode in HgTe). While the parameters of the fundamental lattice modes are closely similar, the temperature dependences of the low-frequency modes of the two alloy systems are radically different. Their thermal activation energies for the HgZnTe and HgCdTe alloys are 3.3 and 50.0 meV, respectively. The results of the experiment are treated in terms of the double-well potential model for the Hg atom in the alloy lattice.