Possible Superconductivity Approaching Ice Point

TL;DR

This study uses first-principles calculations to explore how substituting chalcogen atoms affects superconductivity in hydrogen chalcogenides under high pressure, predicting a potential record critical temperature of 280 K.

Contribution

It systematically analyzes the impact of atomic substitutions on superconductivity, highlighting the roles of atomic mass and covalent metallicity, and predicts a new high-temperature superconductor.

Findings

Critical temperature varies with substitution rate.

A new compound H3S0.925P0.075 may reach 280 K.

Low atomic mass and covalent metallicity are key factors.

Abstract

Recently BCS superconductivity at 203 K has been discovery in a highly compressed hydrogen sulfide. We use first-principles calculations to systematically examine the effects of partially substituting the chalcogen atoms on the superconductivity of hydrogen chalcogenides under high pressures. We find detailed trends of how the critical temperature changes with increasing the V-, VI- or VII-substitution rate, which highlight the key roles played by low atomic mass and by strong covalent metallicity. In particular, a possible record high critical temperature of 280 K is predicted in a stable H3S0.925P0.075 with the Im-3m structure under 250 GPa.