Hydrogenation-induced high-temperature superconductivity in two-dimensional molybdenum carbide Mo2C3

Abstract

Two-dimensional (2D) superconductors have important potential applications in constructing nano superconducting devices, thus, 2D superconductors with high critical temperature (T c ) are highly desired. Till now, the T c of 2D superconductors are still relatively low. Based on density functional first-principles calculations, we predicted a new stable 2D transition metal molybdenum carbide 2H-Mo2C3. Based on the Eliashberg theory, we predict that it is not a superconductor. However, after hydrogenation, the hydrogen atoms increase the electronic density of states at the Fermi level, and strengthen the electron-phonon coupling. Accordingly, the hydrogenated 2H-Mo2C3, i.e., 2H-Mo2C3H2, is a 2D superconductor with T c of 53 K, exceeding the McMillan limit. Thus, hydrogenation is an important strategy for obtaining 2D high-temperature superconductors at atmosphere pressure. In view of the high superconducting T c of 2H-Mo2C3H2, it is highly expected to be synthesized in future experiments.