Pressure-induced superconductivity in tantalum superhydrides

Abstract

The quest for high-temperature superconductivity in pressure-stabilized hydrides has received great interests due to the recent findings of CaH6, LaH10, YH6, YH9 and H3S with superconducting critical temperature, Tc, above 200 K and at a pressure range of 155–201 GPa. In this work, we conduct extensive structure-searching simulations for the Ta–H system at a pressure range of 300–400 GPa. As a result, we predict several stable pressure-stabilized phases, such as TaH10, TaH11, TaH16 and TaH17. These predicted structures consist of molecular and atomic hydrogen units, where the latter holds the key to improve the superconductivity of the system. Among these high-Tc candidates, tetragonal TaH16 phase, with the large hydrogen content of ∼84 %, exhibits a high Tc value of 196 K at 400 GPa. Our current results could be helpful for the future design of high-temperature superconductivity in the system of transition metal superhydrides under high pressure.