Interplay of structure and superconductivity in α-SnS tuned by pressure

The emergent structure under high pressure introduces a distinctive lattice arrangement, deviating from conventional configurations and offering a unique landscape for exploring intriguing properties, especially in the domain of superconductivity. Here, we have systematically investigated the structural evolution and electrical properties of \ensuremath{\alpha}-SnS under high pressure. The x-ray diffraction results indicate that SnS undergoes two phase transitions at 16.8 and 49.7 GPa, representing a second-order Pnma to Cmcm transition and a first-order Cmcm to $Pm\overline{3}m$ transition. In addition, single-crystal in situ high-pressure Raman spectroscopy experiments have confirmed it. Electrical transport measurements demonstrate the transition of SnS from a semiconductor to a metal and then to a superconductor under high pressure, intricately linked to a structural transition and an increase in the hole carrier concentration. Combined with our first principles calculation, it is determined that the topological properties and superconductivity coexist in SnS with the $Pm\overline{3}m$ phase. The nonmonotonic variation of ${T}_c$ in SnS with pressure is attributed to the electron-phonon coupling effect. Additionally, this study marks a confirmation of the structural phase transitions in SnS under high pressure. Our study contributes to a deeper understanding of the intricate relationship between structure and performance in extreme conditions.