Phonon-mediated superconductivity in charge doped and Li-deposited two dimensional C3N

Abstract

By using first-principles calculations, we investigate the electron-phonon interaction and phonon-mediated superconductivity of charge doped and Li-deposited monolayer C3N. No superconductivity is found for 0.2 e/cell doped C3N due to a small electron-phonon coupling (EPC) strength which is less that 0.1. Surprisingly, when Li atom is deposited the monolayer, much more low lying optical phonon modes especially the out-of-plane vibration mode participate the EPC process. This results in a pronounced boost of EPC constant to 0.86 and the transition temperature Tc obtained according to isotropical McMillan–Allen–Dynes formula reaches 13.03 K, which is higher than 8.1 K of Li-deposited graphene and 1.4 K of Ca-deposited graphene. Our findings not only widening the potential application of the intriguing two-dimensional material C3N, but also enrich the world of two dimensional superconductors with a relatively high Tc.