Pressure-induced high-temperature superconductivity in ternary Y-Zr-H compounds

TL;DR

This study discovers novel Y-Zr-H hydrides with high-temperature superconductivity at various pressures, emphasizing the role of hydrogen in electron-phonon interactions and opening new paths for designing superconductors.

Contribution

The paper reports the identification of new Y-Zr-H hydrides with high Tc and stability at low pressures, advancing understanding of hydrogen's role in superconductivity.

Findings

YZrH6 stable down to 0.01 GPa with Tc of 16 K

YZrH8 exhibits Tc of 70 K at 200 GPa

YZrH12 exhibits Tc of 183 K at 160 GPa

Abstract

Compressed hydrogen-rich compounds have received extensive attention as appealing contenders for superconductors, and further challenges are maintaining the stability and superconductivity of hydrides at lower pressures. In this work, we found several novel hydrides YZrH6, YZrH8 and YZrH12 with excellent superconductivity in the Y-Zr-H ternary system. Interestingly, YZrH6 with an A15-type structure can maintain dynamic stability down to 0.01 GPa and still with a critical temperature (Tc) of 16 K. YZrH8 and YZrH12 have high Tc of 70 K and 183 K at 200 GPa and 160 GPa, respectively. The phonon modes associated with H atoms contribute significantly to the electron-phonon coupling, and the H-driven electronic density of states play an important role in superconductivity. These findings highlight relationship between the H-driven electronic density of states, electron-phonon coupling and the superconductivity in a distinct class of hydrides, opening new avenues for designing and optimizing new hydrogen-rich high temperature superconductors.