Potential high- <i> T _c </i> superconducting lanthanum and yttrium hydrides at high pressure

TLDR

A systematic structure search and phonon calculations in La‑H and Y‑H systems under high pressure identified hydrogen‑rich, dynamically stable structures that, according to BCS theory, could be high‑Tc superconductors. LaH10 adopts a sodalite‑like fcc structure stable above 200 GPa with a predicted Tc of 274–286 K at 210 GPa, while YH10 is predicted to be stable in a similar fcc structure with a Tc of 305–326 K at 250 GPa, indicating that such dense hydrides could be a new class of very high‑temperature superconductors.

Abstract

A systematic structure search in the La-H and Y-H systems under pressure reveals some hydrogen-rich structures with intriguing electronic properties. For example, LaH10 is found to adopt a sodalite-like face-centered cubic (fcc) structure, stable above 200 GPa, and LaH8 a C2/m space group structure. Phonon calculations indicate both are dynamically stable; electron phonon calculations coupled to Bardeen-Cooper-Schrieffer (BCS) arguments indicate they might be high-Tc superconductors. In particular, the superconducting transition temperature Tc calculated for LaH10 is 274-286 K at 210 GPa. Similar calculations for the Y-H system predict stability of the sodalite-like fcc YH10 and a Tc above room temperature, reaching 305-326 K at 250 GPa. The study suggests that dense hydrides consisting of these and related hydrogen polyhedral networks may represent new classes of potential very high-temperature superconductors.