Superconductivity in functionalized niobium-carbide MXenes
arXiv:2208.13678 · doi:10.1039/D3NR00347G
Abstract
We show the effect of Cl and S functionalization on the superconducting properties of layered (bulk) and monolayer niobium carbide (NbC) MXene crystals, based on first-principles calculations combined with Eliashberg theory. For the bulk layered NbCCl, the calculated superconducting transition temperature () is in very good agreement with the recently measured value of 6 K. We show that is enhanced to 10 K for monolayer NbCCl, due to an increase in the density of states at the Fermi level, and the corresponding electron-phonon coupling. We further demonstrate a feasible gate-induced enhancement of up to 40 K for both bulk-layered and monolayer NbCCl crystals. For the S-functionalized cases our calculations reveal the importance of phonon softening in understanding their superconducting properties. Finally, we predict that NbCS in bulk-layered and monolayer form is potentially superconducting, with a around 30 K. Considering that NbC is not superconducting in pristine form, our findings promote functionalization as a pathway towards robust superconductivity in MXenes.
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