Superconductivity in RbH$_{12}$ at low pressures: an \emph{ab initio} study

TL;DR

This study uses first-principles calculations to identify low-pressure stable phases of RbH12 that are metallic and potentially superconducting at temperatures up to 111 K, aiming for practical ambient-pressure applications.

Contribution

It demonstrates the potential for stabilizing RbH12 phases at low pressures with quantum anharmonic effects, advancing the pursuit of ambient-pressure superconductivity in hydrides.

Findings

Identified five competing phases between 0 and 100 GPa.

Found metastable phases possibly stable at as low as 10 GPa.

All phases exhibit metallicity with Tc between 46 and 111 K.

Abstract

High-pressure polyhydrides are leading contenders for room temperature superconductivity. The next frontier lies in stabilizing them at ambient pressure, which would allow their practical applications. In this first-principles computational study, we investigate the potential for record-low pressure stabilization of binary superhydrides within the RbH$_{12}$ system including lattice quantum anharmonic effects in the calculations. We identify five competing phases for the pressure range between 0 and 100 GPa. Incorporating anharmonic and quantum effects on ion dynamics, we find the $Immm$ and $P6_3/mmc$ phases to be the most probable, potentially metastable even at pressures as low as 10 GPa. Notably, all phases exhibit metallic properties, with critical temperatures between 46 and 111 K within the pressure range they are dynamically stable. These findings have the potential to inspire future experimental exploration of high-temperature superconductivity at low pressures in Rb-H binary compounds.