Pressure-induced superconductivity in the metal thiophosphate Pb2P2S6

We report on the pressure-tuning of the physical properties of a metal thiophosphate ${\mathrm{Pb}}_{2}{\mathrm{P}}_{2}{\mathrm{S}}_{6}$. Resistance measurements evidence a semiconducting-to-metallic transition at around 39 GPa and immediate emergence of superconductivity. The superconducting critical temperature ${T}_{C}$ monotonously increases from 3.2 to 5.1 K until the highest studied pressure 54 GPa. Over the whole pressure range, the pristine monoclinic lattice symmetry is not changed. Moreover, the resonance Raman scattering is observed in the range of 8--12 GPa depending on the excitation energy used. These findings establish ${\mathrm{Pb}}_{2}{\mathrm{P}}_{2}{\mathrm{S}}_{6}$ as a new platform to explore intrinsic metallization and superconductivity, which may promote developments of relevant applications.