Theoretical study on superconductivity of Ce–Ca–H ternary hydrides under high pressure

In this work, we used genetic algorithm combined with density functional theory (DFT) calculations to search for the structures of the pressure-induced ternary hydrides CeCaxHy (x=1–3, y = 1–24). The crystal structures and electronic properties of CeCaxHy in the pressure range of 100–300 GPa were systematically studied. The calculated results showed that structures of P4/mmm-CeCaH8, Cmmm-CeCaH8, Cmmm-CeCaH12 and Fm-3m-CeCa3H24 could be stable in pressure range of 150–300 GPa. The predicted superconducting transition temperature (Tc) values were 90, 86 and 150 at 150 GPa for P4/mmm-CeCaH8, Cmmm-CeCaH8 and Cmmm-CeCaH12, respectively, and the Fm-3m-CeCa3H24 structure had a Tc of 201 K at 300 GPa. Also, the mechanical properties of the Ce–Ca–H most stable phases were discussed.