The superconductivity and electron-doping effect in MgP2H14 hydrides.

Room temperature superconductivity has become the tireless pursuit of scientists due to its epoch-making significance. Inspired by the recently predicted high superconductivity in LiP2H14, we identify a new superconductor MgP2H14 by substituting Li with Mg and prove its stability. The superconducting critical temperature (T c) and electron-phonon coupling (EPC) parameters (λ) of MgP2H14 under 280 GPa are predicted to be ∼166 K and ∼1.65, respectively; the high superconductivity of MgP2H14 mainly arises from the strong electron-phonon interaction between H 1s electrons and the H-associated vibration. Furthermore, in hydrogen-based superconductors, the hydrogen sublattice will gain more electrons by doping extra metal atoms or replacing the original metals with higher valence electrons metals. However, if these electrons do not form newly occupied states on the hydrogen energy level near the Fermi level, the superconductivity will not improve further. Our findings provide clues for designing and modulating the superconductivity.