Room-Temperature Superconductivity at 298 K in Ternary La-Sc-H System at High-pressure Conditions

Abstract Room-temperature superconductor has been a century-long dream of humankind. Recent research on hydrogen-based superconductors (e.g., CaH6, LaH10, etc.) at high-pressure conditions lifts the record of superconducting critical temperature (Tc) up to ~250 kelvin. We here report the experimental synthesis of the first-ever room-temperature superconductor by compression on a mixture of La-Sc alloy and ammonia borane at pressures of 250-260 gigapascals (GPa) via a diamond anvil cell by a laser-heating technique. Superconductivity with an onset temperature of 271-298 kelvin at 195-266 GPa is observed by the measurement of zero electrical resistance and the suppression of Tc under applied magnetic fields. Synchrotron X-ray diffraction data unambiguously reveal that this superconductor crystallizes in a hexagonal structure with a stoichiometry LaSc2H24, in excellent agreement with our previous prediction1. Through thirteen reproducible experimental runs, we provide solid evidence of the realization of a room-temperature superconductor for the first time, marking a milestone in the field of superconductivity.