Superconductivity of monolayer Mo$_2$C: the key role of functional groups

Abstract: Monolayer Mo$_2$C is a new member of two-dimensional materials. Here the electronic structure and lattice dynamics of monolayer Mo$_2$C are calculated. According to the electron-phonon interaction, it is predicted that monolayer Mo$_2$C could be a quasi-two-dimensional superconductor and the effects of functional-groups are crucially important considering its unsaturated surface. Despite the suppressed superconductivity by chalcogen adsorption, our most interesting prediction is that the electron-phonon interaction of monolayer Mo$_2$C can be greatly enhanced by bromine absorbtion, suggesting that Mo$_2$CBr$_2$ as a good candidate for nanoscale superconductor.