Predicted high-temperature superconductivity in rare earth hydride ErH2 at moderate pressure

TL;DR

This study predicts that the rare earth hydride ErH2 can exhibit high-temperature superconductivity around 80 K at a relatively low pressure of 14.5 GPa, with complex magnetic interactions influencing its properties.

Contribution

It is the first to demonstrate superconductivity in ErH2 at moderate pressures using density functional theory, revealing new insights into pressure effects and magnetic phenomena in hydrides.

Findings

Superconductivity in ErH2 at 14.5 GPa with Tc around 80 K

Fermi surface nesting and Kondo effect observed at low pressure

Band structure gap and magnetic susceptibility changes at 20 GPa

Abstract

Hydrides offer an opportunity to study high-temperature (Tc) superconductivity at experimentally achievable pressures. However, they remained extremely high. Using density functional theory calculations, herein we demonstrated that a newly rare earth hydride, namely bulk ErH2, could be superconducting with a Tc around 80 K at 14.5 GPa. To date, the drived pressure is the lowest reported value for compressed hydrides. Besides superconductivity, Fermi Surface nesting and Kondo effect were manifested at this pressure. Intriguingly, due to Kondo destruction, superconductivity was prone to exist at 15 GPa. Under the rest of applied pressures, we also revealed a gap of band structure at 20 GPa on the background of normal metallic states. At 20 GPa, this compressed system could act as a host of superconductor being judged from a sharp jump of spontaneous magnetic susceptibility with an evanescent spin density of state at Fermi level along with the competition between spin density wave and superconductivity. Finally, electron pairing glue for ErH2 at these three typical pressures was attributed to the antiferromagnetic spin fluctuation.