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 (T-c similar to 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 T-c of similar to 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 H-2 molecules and is not a good superconductor. The extra electrons introduced break up the H-2 molecules, increasing the amount of atomic hydrogen compared with the parent hydride, which is necessary for stabilizing the clathrate structure or other high-T-c 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-T-c superconductors in a variety of ternary or quaternary hydrides.