Prediction of High Temperature Superconductivity in C2/c-24 Solid Hydrogen

TL;DR

This study predicts that solid hydrogen in the C2/c-24 phase exhibits high-temperature superconductivity with a transition temperature of 242 K at 500 GPa, using advanced electron-phonon coupling calculations.

Contribution

It provides the first detailed computational analysis of superconductivity in the C2/c-24 phase of solid hydrogen at high pressures.

Findings

Superconducting transition temperature of 242 K at 500 GPa.

Rapid increase in transition temperature between 400-500 GPa.

High-pressure phase remains in C2/c-24 structure up to at least 500 GPa.

Abstract

Recent experimental developments in hydrogen-rich materials in high pressures have put this class of materials above others in the race toward room temperature superconductivity. As it is the basis of all the materials in this class, the efforts to determine the properties of pure solid hydrogen at high pressures remain intense. Most notably, a recent experimental study of the metallization of hydrogen identified the crystal phase of the solid as the C2/c-24 molecular phase up to ~425 GPa. It is possible that the observed metallization is caused by band structure effects and not a structural phase transition, and the material remains in this crystal phase up to higher pressures. Therefore it is of crucial importance to determine the superconducting properties of the C2/c-24 phase. Here, we employ a Wannier function-based dense k-point and q-point sampling to compute the electron-phonon coupling and superconducting properties of molecular hydrogen in the C2/c-24 phase. We find that the material has a high superconducting transition temperature of 242 K at 500 GPa. We also find that the transition temperature rapidly increases with pressure in the 400 - 500 GPa range.