Superconductivity of Thulium Substituted Clathrate Hexahydrides at Moderate Pressure

Abstract

Due to the BCS theory, hydrogen, the lightest element, would be the prospect of room-temperature superconductor after metallization, but because of the difficulty of the hydrogen metallization, the theory about hydrogen pre-compression was proposed that the hydrogen-rich compounds could be a great option for the high T_c superconductors. The superior properties of TmH₆, YbH₆ and LuH₆ indicated the magnificent potential of heavy rare earth elements for low-pressure stability. Here, we designed XTmH₁₂ (X = Y, Yb, Lu, and La) to obtain higher T_c while maintaining low pressure stability. Most prominently, YbTmH₁₂ can stable at a pressure of 60 GPa. Compared with binary TmH₆ hydride, its T_c was increased to 48 K. The results provide an effective method for the rational design of moderate pressure stabilized hydride superconductors.