Enthalpy stabilization of superconductivity in an alloying S-P-H system: First-principles cluster expansion study under high pressure

The metallic ternary compound phase of S-P-H material is predicted to be the ground-state structure by first principles cluster expansion. We find that the S0.75P0.25H3, S0.5P0.5H3, and S0.25P0.75H3 structures are thermodynamically stable. The characteristic of phonon dispersions shows that the S0.75P0.25H3 and S0.5P0.5H3 structures are dynamically stable at 200 GPa. The solution of the Fermi surface supports the values of superconducting transition temperature (Tc). In addition, the electron localization function and the projected crystal orbital Hamilton populations reveal that the nature of chemical bonding shows the degree of covalent bonding of the S0.75P0.25H3 and S0.5P0.5H3 structures, supporting the Tc value. Our results show that the S0.5P0.5H3 structure is the highest Tc among the S-P-H system. The Tc of the S0.5P0.5H3 structure is estimated to be 89 K at 200 GPa.

Automated summary

By first principles cluster expansion, the metallic ternary compound phase of S-P-H material is predicted to be the ground-state structure, with the S0.75P0.25H3 and S0.5P0.5H3 structures thermodynamically stable, supported by the solution of the Fermi surface for the values of superconducting transition temperature. The highest Tc among the S-P-H system is found to be 89 K at 200 GPa for the S0.5P0.5H3 structure.