Stoichiometric Ternary Superhydride LaBeH8 as a New Template for High-Temperature Superconductivity at 110 K under 80 GPa

The search for high-temperature superconducting superhydrides has recently moved into a new phase by going beyond extensively probed binary compounds and focusing on ternary ones with vastly expanded material types and configurations for property optimization. Theoretical and experimental works have revealed promising ternary compounds that superconduct at or above room temperature, but it remains a pressing challenge to synthesize stoichiometric ternary compounds with a well-resolved crystal structure that can host high-temperature superconductivity at submegabar pressures. Here, we report on the successful synthesis of ternary LaBeH8 obtained via compression in a diamond anvil cell under 110–130 GPa. X-ray diffraction unveils a rocksalt-like structure composing La and BeH8 units in the lattice. Transport measurements determined superconductivity with critical temperature Tc up to 110 K at 80 GPa, as evidenced by a sharp drop of resistivity to zero and a characteristic shift of Tc driven by a magnetic field. Our experiment establishes the first superconductive ternary compound with a resolved crystal structure. These findings raise the prospects of rational development of the class of high-Tc superhydrides among ternary compounds, opening greatly expanded and more diverse structural space for exploration and discovery of superhydrides with enhanced high-Tc superconductivity.Received 10 May 2022Revised 16 January 2023Accepted 18 May 2023DOI:https://doi.org/10.1103/PhysRevLett.130.266001© 2023 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasPressure effectsSuperconducting phase transitionPhysical SystemsHigh-temperature superconductorsHydridesUnconventional superconductorsTechniquesCrystal structuresPressure techniquesResistivity measurementsX-ray diffractionCondensed Matter, Materials & Applied Physics