The 6th International Conference on Matter and Radiation at Extremes (ICMRE2023)

119 / 2023-04-14 11:24:01

Probing the high-pressure structure of hydrogen-rich tantalum hydrides via CALYPSO

structure prediction; superconductivity; hydrides

High Pressure Physics and Materials Science > Hydrogen and high-energy density material-poster

It's a long-held dream for scientists to search room-temperature superconductivity. In 2004, Ashcroft scientifically suggested that compressed H-rich materials have the potential for becoming the good candidate for high-temperature superconductivity. The wisdom has provoked a wave of searching for superconductivity in a flurry of hydrogen-dominated materials under high pressure. Recently, the remarkable theoretical prediction and subsequent experimental discovery of superconductivity ~ 260 K in LaH₁₀ under high pressure rekindled the century-old dream of a room temperature superconductor. In-depth analysis indicates the high-temperature superconductivity is normally attributed to a large hydrogen-dominant electron DOS at the Fermi level. It is well known that transition metals that is able to accommodate more atomic hydrogen due to the large valence electron density. Herein, we explored hydrogen-rich tantalum hydrides at a pressure range of 300 and 400 GPa by using our in-house developed CALYPSO structure prediction method in conjunction with first-principles density functional calculations. We identify several hitherto unknown stoichiometries, such as TaH₁₀, TaH₁₁, TaH₁₆ and TaH₁₇. Moreover, the electron-phonon coupling (EPC) calculation unveil that the T_c of newly predicted TaH₁₆ could reach 196 K at 400 GPa. The present results could give the vital insight into intensively studying about the transition metal hydrides.