Crystal structures and promising superconductivity in Sc-S system under high pressure

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Chemistry

Background:

• Superconducting materials are crucial for energy and technology.
• Exploring new superconductors under high pressure is an active research area.
• Sulfides are a promising class of materials for high-temperature superconductivity.

Purpose of the Study:

• To systematically investigate the crystal structures and electronic properties of the scandium-sulfur (Sc-S) system under high pressure.
• To identify stable Sc-S stoichiometries and predict their superconducting properties.
• To elucidate the underlying mechanisms of superconductivity in the Sc-S system.

Main Methods:

• Density Functional Theory (DFT) calculations for structural and electronic properties.
• Systematic structure searching and energy calculations across a pressure range of 20-200 GPa.
• Electron-phonon coupling (EPC) calculations to determine superconducting critical temperature (Tc).

Main Results:

• Several stable Sc-S stoichiometries were identified, including ScS3, ScS2, Sc2S, and Sc3S.
• Sc3S was predicted to be stable at 200 GPa, exhibiting a superconducting critical temperature (Tc) of approximately 25 K.
• Electron-phonon coupling in Sc3S is mediated by Sc phonons and Sc 3d electrons at the Fermi level.

Conclusions:

• The Sc-S system offers potential for novel superconducting materials under high pressure.
• Sc3S is a promising candidate for high-pressure superconductivity.
• The findings provide a theoretical basis for experimental studies on Sc-S compounds.