Prediction of Ambient Pressure Conventional Superconductivity above 80K in Thermodynamically Stable Hydride Compounds

TL;DR

This paper predicts thermodynamically stable hydride compounds that could exhibit high-temperature superconductivity above 80K at ambient pressure, using machine learning and high-throughput screening.

Contribution

It introduces a new family of stable hydrides with potential for ambient-pressure high-temperature superconductivity, identified through a large-scale computational approach.

Findings

Predicted superconducting temperatures of 45-80K, possibly above 100K with doping.

Identified stable compounds suitable for experimental synthesis.

Demonstrated the feasibility of achieving high-Tc superconductivity at room pressure.

Abstract

The primary challenge in the field of high-temperature superconductivity in hydrides is to achieve a superconducting state at ambient pressure rather than the extreme pressures that have been required in experiments so far. Here, we propose a family of compounds, of composition Mg$_2$XH$_6$ with X$=$Rh, Ir, Pd, or Pt, that achieves this goal. These materials were identified by scrutinizing more than a million compounds using a machine-learning accelerated high-throughput workflow. They are thermodynamically stable, indicating that they are serious candidates for experimental synthesis. We predict that their superconducting transition temperatures are in the range of 45-80K, or even above 100K with appropriate electron doping of the Pt compound. These results indicate that, although very rare, high-temperature superconductivity in thermodynamically stable hydrides is achievable at room pressure.