Pressure Effects in Phonon Modes and Structure of A II B 2 III C 4 IV Compounds and Combinations

Abstract

A II B 2 III C 4 VI compounds have been prepared with A II =Zn, Cd, Mn, B III =In, and C VI =S, Se. These atomic substitutions induce modifications in the structure and frequency for some of the phonons. These compounds have been studied by Raman spectroscopy at ambient conditions and under hydrostatic pressures. All phonons appear in the spectral region below 400 cm m 1 . High-pressure measurements have shown the existence of soft modes. New modes seem to appear at high pressures due to the phonon splitting. All low frequency phonons of the Zn 0.6 Mn 0.4 In 2 S 4 compound show a sudden modification in the frequency dependence on pressure above ∼2 GPa. Based on the Raman results we propose an assignment for the modes and try to extract information about the structure and the possible phase transitions.