Potential high-Tc superconductivity in CaYH12 under pressure

The high-pressure phases and superconductivity of CaYH12 have been explored by using a particle swarm optimization structure prediction methodology in combination with first-principles calculations. Our results show that CaYH12 becomes stable with a cubic Fd3¯m structure above 170 GPa, where metal atoms form body-centered-cubic (bcc) lattices and hydrogens occupy all the tetrahedral interstices of these bcc lattices, completing sodalitelike cages. The electron-phonon coupling calculations indicate that the Fd3¯m structure is a potential high-temperature superconductor, with a calculated Tc of 258 K at 200 GPa. Our current study provides a possibility for searching new high-Tc superconductors in ternary hydrides.