Superconducting ScH3 and LuH3 at Megabar Pressures

Rare-earth (RE) superhydrides have great potential as high-temperature superconductors, with recent discoveries almost achieving room-temperature superconductivity in compressed LaH10 and YH9. Here, we continue to study the rare-earth hydrides by focusing on the new hydrides that the lightest element Sc and the heaviest element Lu formed under pressure. Two new superconducting hydrides ScH3 (T-c similar to 18.5 K at 131 GPa) and LuH3 (T-c similar to 12.4 K at 122 GPa) have been identified both with cubic structure by combining X-ray diffraction and electrical resistance techniques. Among all of the REH3, only the superconducting properties of ScH3 and LuH3 have been experimentally confirmed. Our current results may offer guidance to other REH3, which were predicted to be superconductors but have not been experimentally confirmed.