Observation of Superconductivity above 200 K in Pressure-Stabilized Cubic (Y,Ce)H 10

Clathrate hydrides have attracted considerable attention for their high-temperature superconductivity under high pressure, motivating the enhancement of their superconducting temperature ( T c ) through metal doping as a compelling pursuit. Here, we introduce relatively lighter Y into the Ce–H system to tailor its superconductivity, yielding a substituted face-centered cubic (Y,Ce)H 10 phase that incorporates a crucial YH 10 structural motif unattainable in the binary Y–H system. Remarkably, the resulting (Y,Ce)H 10 exhibits superconductivity with a maximum T c of 206 K, an ∼80% enhancement relative to CeH 10, placing it among the very few hydride superconductors that surpass the 200 K regime. Our results demonstrate that the metal element exerts a crucial influence on the superconductivity of clathrate hydrides, with the presence of YH 10 units clearly enhancing superconductivity and underscoring elemental substitution as a feasible strategy to further promote superconductivity.