Second group of high-pressure high-temperature lanthanide polyhydride superconductors

Rare-earth polyhydrides formed under pressure are promising conventional superconductors, with the critical temperature T-c in compressed LaH10 almost reaching room temperature. Here, we report a systematic computational investigation of the structural and superconducting properties of rare-earth (RE) polyhydrides formed under pressure across the whole lanthanide series. Analyses of the electronic and dynamical properties and electron-phonon coupling interaction for the most hydrogen-rich hydrides REH, (n = 8, 9, 10) that can be stabilized below 400 GPa show that enhanced T-c correlates with a high density of H s states and low number of RE f states at the Fermi level. In addition to previously predicted and measured LaH10 and CeH9, we suggest YbH10 and LuH8 as additional potential high-T, superconducters. They form a second island of high-T, superconductivity amongst the late lanthanide polyhydrides, with an estimated T-c of 102 K for YbH10 at 250 GPa.