Ab initio design of novel 2D materials: Janus functionalized Mxenes (M2XTT’)

Abstract

Functionalized MXenes have been experimentally proved for potential applications in capacitance and catalysis. However, there is less systematical study on the polarization reversal of Janus MXenes. Here, we propose a novel asymmetric Janus functionalized MXenes (M2XTT’) based on first-principles calculations. We find M2XTT’ can be semiconductive or metallic, and the M_d orbitals dominate their conductivity. Specifically, wurtzite-like Zr2NOF has a small band gap, indicating its possible semimetal properties at room temperature. A few structures are spontaneously polarized with high piezoelectric constant. Importantly, the polarized direction and electronic structure of those M2XTT’, show phase-dependent features, leading to potential applications in novel nanodevices such as capacitance or sensors. Our theoretical calculations may provide guidelines for potential experimental realization on Janus functionalized MXenes.