Electronic structure of nitrogen-doped lutetium hydrides

Hydrides at high pressures constitute the only materials to be superconducting above 200 K, and are typically marked by an appreciable hydrogen density of states and van Hove singularities at the Fermi energy. Given the recent interest in nitrogen-doped lutetium hydride, the authors focused on finding the structures which would have electronic properties that could plausibly support high-temperature superconductivity within a narrow pressure range. They have identified a narrow range of stoichiometries Lu${}_{8}$H${}_{23\ensuremath{-}x}$N with hydrogen-dominant conduction states, and found one structure which exhibits a very large hydrogen density of states with an extremely sharp van Hove singularity, whose properties may therefore change dramatically under pressure.