High-pressure behavior of Raman modes in CuGaS2.

Abstract

The Raman-active modes of ${\mathrm{CuGaS}}_{2}$ have been investigated at ambient temperature under high pressure using neon gas as pressure transmitting medium up to 18 GPa. An assignment of the symmetry of the zone-center modes is proposed on the basis of their pressure dependence as compared to that of the corresponding modes in zinc-blende ZnS. Under quasihydrostatic conditions and in the absence of shear stress, no broadening of lattice modes occurs prior to the transition and the metastability of the chalcopyrite lattice is shown to extend to at least 18.4 GPa, which is well into the domain of stability of the high-pressure rocksalt phase.