Theoretical Predictions on Superconducting Phase above Room Temperature in Lutetium-Beryllium Hydrides at High Pressures

High-pressure structural search was performed on the hydrogen-rich compound LuBeH₈ at pressures up to 200 GPa. We found an $Fm\overline{3}m$ structure that exhibits stability and superconductivity above 100 GPa. Our phonon dispersion, electronic band structure, and superconductivity analyses in the 100–200 GPa pressure range reveal a strong electron–phonon coupling in LuBeH₈, while the superconducting critical temperature T_c shows a decreasing trend as the pressure increases, with T_c = 255 K at 200 GPa and maximal T_c = 355 K at 100 GPa. This study demonstrated the room-temperature superconductivity in $Fm\overline{3}m$-LuBeH₈, thus enriching the family of ternary hydrides. These findings provide valuable guidance for identifying new high-temperature superconducting hydrides.