Giant enhancement of superconducting critical temperature in substitutional alloy (La,Ce)H<sub>9</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36216828.
- Also identified by DOI 10.1038/s41467-022-33743-6 and PMC identifier 9551097.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
A sharp focus of current research on superconducting superhydrides is to raise their critical temperature T<sub>c</sub> at moderate pressures. Here, we report a discovery of giant enhancement of T<sub>c</sub> in CeH<sub>9</sub> obtained via random substitution of half Ce by La, leading to equal-atomic (La,Ce)H<sub>9</sub> alloy stabilized by maximum configurational entropy, containing the LaH<sub>9</sub> unit that is unstable in pure compound form. The synthesized (La,Ce)H<sub>9</sub> alloy exhibits T<sub>c</sub> of 148-178 K in the pressure range of 97-172 GPa, representing up to 80% enhancement of T<sub>c</sub> compared to pure CeH<sub>9</sub> and showcasing the highest T<sub>c</sub> at sub-megabar pressure among the known superhydrides. This work demonstrates substitutional alloying as a highly effective enabling tool for substantially enhancing T<sub>c</sub> via atypical compositional modulation inside suitably selected host crystal. This optimal substitutional alloying approach opens a promising avenue for synthesis of high-entropy multinary superhydrides that may exhibit further increased T<sub>c</sub> at even lower pressures.