Crystal Structures and Promising Superconductivity in Sc-S System under High Pressure

Abstract In this work, we performed systematic simulations on the crystal structures and electronic properties of Sc-S crystalline system at a pressure range of 20 to 200 GPa. Our results reveal several stable stoichiometries, such as ScS3, ScS2, Sc2S, and Sc3S. The further electron-phonon simulations indicate that Sc3S exhibits a superconducting critical temperature (Tc) of approximately 25 K at 200 GPa. Our in-depth analysis shows that such electron-phonon coupling is primarily mediated by the Sc phonons in the mid-frequency region and the Sc 3d electrons at the Fermi level. Our current findings not only offer insights into the exploration of new superconducting sulfides but also provide a direction for future experimental investigations of Sc-S system under high pressure.