Route to a Superconducting Phase above Room Temperature in Electron-Doped Hydride Compounds under High Pressure

The recent theory-orientated discovery of record high-temperature superconductivity (Tc∼250 K) in sodalitelike clathrate LaH10 is an important advance toward room-temperature superconductors. Here, we identify an alternative clathrate structure in ternary Li2MgH16 with a remarkably high estimated Tc of ∼473 K at 250 GPa, which may allow us to obtain room-temperature or even higher-temperature superconductivity. The ternary compound mimics a Li- or electron-doped binary hydride of MgH16. The parent hydride contains H2 molecules and is not a good superconductor. The extra electrons introduced break up the H2 molecules, increasing the amount of atomic hydrogen compared with the parent hydride, which is necessary for stabilizing the clathrate structure or other high-Tc structures. Our results provide a viable strategy for tuning the superconductivity of hydrogen-rich hydrides by donating electrons to hydrides via metal doping. Our approach may pave the way for finding high-Tc superconductors in a variety of ternary or quaternary hydrides.