Synthesis of superconducting SbS and SbS2 antimony chalcogenide compounds at high pressures

Abstract

New functional materials based on chalcogenides have promising significant applications spanning from field-effect transistors to electronic and optovalleytronic devices, and even to superconductivity. Here we report two chalcogenide materials SbS and $\mathrm{Sb}{\mathrm{S}}_{2}$, obtained in pressure-induced decomposition of ${\mathrm{Sb}}_{2}{\mathrm{S}}_{3}$ at 26.3 GPa. Different from the semiconducting ${\mathrm{Sb}}_{2}{\mathrm{S}}_{3}$ precursor, both SbS and $\mathrm{Sb}{\mathrm{S}}_{2}$ compounds are metallic at high pressure. Superconducting state is observed in the decomposed sample above 42 GPa, signified by a sharp drop of the resistance to zero upon cooling and a decrease of the transition temperature with the external magnetic field. Through diffraction data, SbS is determined as a major component responsible for superconductivity. The measured ${T}_{c}$ has a nearly linear increase with applied pressure, i.e., $d{T}_{c}/dP\ensuremath{\sim}0.1\phantom{\rule{0.16em}{0ex}}\mathrm{K}\phantom{\rule{0.16em}{0ex}}\mathrm{G}{\mathrm{Pa}}^{--1}$, which reaches 6.6 K at 75.0 GPa. The experimental ${T}_{c}$ values are in general agreement with the calculation based on BCS theory, but the trend with pressure is reversed, indicating the abnormal superconducting behavior in SbS. The present results expand the chalcogenide family with two members and also open an avenue in finding the acquisition of superconducting materials in this group.