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.