High-temperature superconductor of sodalite-like clathrate hafnium hexahydride

Abstract

Hafnium hydrogen compounds have recently become the vibrant materials for structural prediction at high pressure, from their high potential candidate for high-temperature superconductors. In this work, we predict HfH6 by exploiting the evolutionary searching. A high-pressure phase adopts a sodalite-like clathrate structure, showing the body-centered cubic structure with a space group of Im3¯m. The frstprinciples calculations have been used, including the zero-point energy, to investigate the probable structures up to 600GPa, and fnd that the Im3¯m structure is thermodynamically and dynamically stable. This remarkable result of the Im3¯m structure shows the van Hove singularity at the Fermi level by determining the density of states. We calculate a superconducting transition temperature (Tc) using Allen-Dynes equation and demonstrated that it exhibits superconductivity under high pressure with relatively high-Tc of 132 K.