Superconductivity and stability study of ASc2H24 (A = Y, La, Ac) under high pressure†
Abstract
Inspired by the high-temperature superconductivity of LaSc2H24 at room temperature, we substitute La with the A-site element and investigate the superconducting and stability properties of the ternary hydrides ASc2H24 (A = Y, La, Ac) under high-pressure conditions. First-principles calculations reveal that the predicted structure AcSc2H24 not only remains dynamically stable under ultrahigh pressures (400–500 GPa) but also exhibits notable superconducting transition temperatures (Tc) around 207.6 K at 400 GPa. Interestingly, as the atomic mass of the A-site element increases, the Tc of the structure gradually decreases, while the density of states (DOS) at the Fermi level also decreases. This trend underscores the critical role of hydrogen-derived DOS at the Fermi level in determining the superconducting performance of these hydrides. In particular, we show that the bonding properties of AcSc2H24 change significantly at 500 GPa, and thus highlight the significance of atom substitution as well as pressure-induced bonding evolution in respect of superconducting material design.