First-principles exploration of superconductivity in MXenes

Abstract

MXenes are an emerging class of two-dimensional materials, which in their thinnest limit consist of a monolayer of carbon or nitrogen (X) sandwiched between two transition metal (M) layers. We have systematically searched for superconductivity among MXenes for a range of transition metal elements, based on a full first-principles characterization in combination with the Eliashberg formalism. Thus, we identified six superconducting MXenes: three carbides (Mo₂C, W₂C and Sc₂C) and three nitrides (Mo₂N, W₂N and Ta₂N). The highest critical temperature of ∼16 K is found in Mo₂N, for which a successful synthesis method has been established [Urbankowski et al., Nanoscale, 2017, 9, 17722–17730]. Moreover, W₂N presents a novel case of competing superconducting and charge density wave phases.