Optical vibration modes in Hg1−xZnxTe solid solutions near q=0

The frequencies of vibration modes at q=0 in Hg 1-x Zn x Te solid solutions are deduced from reflectivity spectra in the infrared. The two reststrahlen bands associated with Te-Hg and Te-Zn vibrations are enough decoupled in frequency to obtain all their parameters from experimental results and to try to deduce an effective charge associated with each of the bonds. The effective charge attributed to Te-Hg is constant with x, on the contrary the one for Te-Zn varies with x Les frequences des modes de vibration a q=0 dans les solutions solides Hg 1-x Zn x Te sont deduites des spectres de reflectivite infrarouge. Les deux bandes associees aux vibrations Te-Hg et Te-Zn sont suffisamment decouplees en frequence pour deduire tous leurs parametres des resultats experimentaux et tenter l'evaluation d'une charge effective associee a chacune de ces liaisons. La charge effective associee a Te-Hg est constante de x, celle associee a Te-Zn au contraire varie avec x