Pressure-induced superconductivity in palladium sulfide

An extend study on PdS is carried out with the measurements of the resistivity, Hall coefficient, Raman scattering, and X-ray diffraction at high pressures up to 42.3 GPa. With increasing pressure, superconductivity is observed accompanying with a metallic phase emerging above 19.5 GPa. The coexistence of semiconducting and metallic phases observed at normal state is confirmed by the Raman scattering and X-ray diffraction between 19.5 and 29.5 GPa. After that, only the metallic normal state phase maintains with an almost constant superconducting transition temperature. These results highlight that the important role of pressure played in inducing superconductivity in these narrow band-gap semiconductors.