Τhe magnetoelectric $\mathrm{ZnC}{\mathrm{r}}_2\mathrm{S}{\mathrm{e}}_4$ spinel, with space group $Fd\overline{3}m$, undergoes a reversible first-order structural transition initiating at 17 GPa, as revealed by our high-pressure x-ray diffraction studies at room temperature. We tentatively assign the high-pressure modification to an $A\mathrm{M}{\mathrm{o}}_2{\mathrm{S}}_4$-type phase, a distorted variant of the monoclinic $\mathrm{C}{\mathrm{r}}_3{\mathrm{S}}_4$ structure. Furthermore, our Raman investigation provides evidence for a pressure-induced insulator-metal transition. Our density functional theory calculations successfully reproduce the structural transition. They indicate significant band gap and magnetic moment reduction accompanying the pressure-induced structural modification. We discuss our findings in conjunction with the available high-pressure results on other Cr-based chalcogenide spinels.

• Received 16 November 2015
• Revised 19 March 2016

DOI:https://doi.org/10.1103/PhysRevB.93.174103