Superconductivity of lithium-doped hydrogen under high pressure

Abstract

The high-pressure lattice dynamics and superconductivity of newly proposed lithium hydrides (LiH2, LiH6and LiH8) have been extensively studied using density functional theory. The application of the Allen–Dynes modified McMillan equation and electron–phonon coupling calculations show that LiH6and LiH8are superconductors with critical temperatures (Tc) of 38 K at 150 GPa for LiH6and 31 K at 100 GPa for LiH8, while LiH2is not a superconductor. TheTcof LiH6increases rapidly with pressure and reaches 82 K at 300 GPa due to enhancement of the electron–phonon coupling and the increased density of states at the Fermi level, while theTcof LiH8remains almost constant.