High pressure structural and vibrational properties of Cu3VS4

We present here high pressure structural and vibrational investigation of a ternary compound Cu3VS4 by means of synchrotron based powder X-ray diffraction and Raman spectroscopy. At ambient conditions it crystallizes in cubic symmetry (P 4 ¯ 3m). Although the cubic lattice remains stable up to about 9 GPa, the diffraction profile and Raman spectra suggest that the V2+ cation exist in two different crystallographic sites (Wyckoff sites: 1a, as in mineral sulvanite, and 1b). Above 5 GPa, emergence of broad quasi elastic Raman scattering indicates that the system undergoes a large electronic changes to metallic nature. Above 10 GPa, the system undergoes a rapid dissociative phase transition into a solid solution of NiAs-type CuS/VS structures with an intermediate tetragonal CuVS2 structure.