Recent experimental developments in hydrogen-rich materials at 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 $C2\text{/}c\text{−}24$ molecular phase up to ∼425 GPa [Loubeyre et al., Nature (London) 577, 631 (2020)]. 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 [Dogan et al., J. Phys.: Condens. Matter 33, 03LT01 (2020)]. Therefore, it is of crucial importance to determine the superconducting properties of the $C2\text{/}c\text{−}24$ 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 $C2\text{/}c\text{−}24$ 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.

• Received 16 July 2021
• Revised 22 December 2021
• Accepted 19 January 2022

DOI:https://doi.org/10.1103/PhysRevB.105.L020509