High-temperature superconductivity in ternary clathrate YCaH ₁₂ under high pressures

Abstract

Binary hydrogen-rich compounds with H clathrate structures can serve as high-temperature superconductors under high pressures. Here, a novel ternary clathrate structure YCaH₁₂ with space group Pm-3m is uncovered at high pressure using ab initio methods. It is predicted that YCaH₁₂ can be stable above 180 GPa and decomposes into YH₆ and CaH₆ above 257 GPa. Our calculations show that YCaH₁₂ is a potential high-temperature superconductor with T _c of 230 K at 180 GPa owing to the strong electron-phonon coupling related to the optical phonon softening of H-cages. The pre-eminent pressure-induced superconductive behavior under attainable pressure is encouraging in the ternary hydrides.