Stability and superconductivity of rare earth metal hydrides with perovskite-structured M ₄ H (M=Sc, Y, La)

Perovskite-structured metal hydrides exhibit excellent stability and good superconductivity at ambient-pressure, making them excellent candidate materials for solving the high stability pressure of hydrogen-rich superconductors. This article uses face centered cubic rare earth metals (M=Sc, Y, La) as the metal skeleton, and inserts a hydrogen atom into the octahedral interstices of the metal skeleton to form a perovskitestructured binary rare earth metal hydride M 4 H (M=Sc, Y, La). The computational structure indicates that in the M 4 H (M=Sc, Y, La) system, multiple energy bands pass through the Fermi surface. The electron density of states near the Fermi surface is mainly contributed by the d orbitals of metal atoms, with a small proportion of H atoms. The analysis of superconductivity indicates that in the M 4 H (M=Sc, Y, La) system, electron-phonon coupling mainly comes from the coupling between low-frequency metal atomic vibrations and electrons of metal atoms near the Fermi surface. The contribution of H atoms to electron-phonon coupling is minimal. Among them, La4H has the largest electron-phonon coupling constant, with a superconducting temperature of 6.07K.