Search for: All records

The search for high-temperature superconductivity among pressure-stabilized hydrides has received great interest since theory-directed clathrate hydrides, such as CaH6, YH6, YH9, and LaH10, were synthesized and shown to exhibit a superconducting critical temperature (Tc) above 200 K. However, further tuning the superconductivity and stability of these prominent hydrides to enhance their applicability remains a significant challenge. Here, we take the sodalite-like clathrate prototype MH6 (M = Ca, Y, etc.) as an example to investigate the stability and superconductivity of multicomponent metal hydrides containing four different metal atoms for each structure. High-throughput simulations of 1820 ABCDH24 quinary hydrides with initial symmetry of F4" 3m, where A, B, C, and D represent different metal atoms were performed. The calculations reveal 119 structures that are dynamically stable at 300 GPa and 67 structures exhibit superconductivity exceeding 200 K, and 20 are found to have Tcs above 260 K. Notable among these quinary alloy hydrides, (Na,Zr,Mg,Hf)H6 is predicted to have a Tc approaching room temperature at 250 GPa. Both configurational and vibrational entropy play important roles in stabilizing these alloy structures. (Na,Y,Zr,Hf)H6, (Mg,Zr,Sc,Y)H6, and (Mg,Hf,Ca,Zr)H6 were computed to be thermodynamically stable, making them promising candidates for experimental synthesis. These quinary superconducting hydrides may facilitate realization of very high-temperature superconductors that are stable over a broader range of conditions than those found for binary or ternary systems.