Prediction of Room-Temperature Superconductivity in Quasi-Atomic H 2 -Type Hydrides at High Pressure.

Achieving superconductivity at room temperature (RT) is a holy grail in physics. Recent discoveries on high-T c superconductivity in binary hydrides H 3 S and LaH 10 at high pressure have directed the search for RT superconductors to compress hydrides with conventional electron-phonon mechanisms. Here, an exceptional family of superhydrides is predicated under high pressures, MH 12 (M = Mg, Sc, Zr, Hf, Lu), all exhibiting RT superconductivity with calculated T c s ranging from 313 to 398 K. In contrast to H 3 S and LaH 10 , the hydrogen sublattice in MH 12 is arranged as quasi-atomic H 2 units. This unique configuration is closely associated with high T c , attributed to the high electronic density of states derived from H 2 antibonding states at the Fermi level and the strong electron-phonon coupling related to the bending vibration of H 2 and H-M-H. Notably, MgH 12 and ScH 12 remain dynamically stable even at pressure below 100 GPa. The findings offer crucial insights into achieving RT superconductivity and pave the way for innovative directions in experimental research.