Theoretical Prediction of the Intrinsic Half-Metallicity in Surface-Oxygen-Passivated Cr₂N MXene

Abstract

Two-dimensional Cr2N MXene as well as surface-passivated Cr2NF2, Cr2N(OH)2, and Cr2NO2 have been investigated using density functional theory. Cr2N is an antiferromagnetic metal. The F atom or OH group-passivation does not change the antiferromagnetic characteristics; however, Cr2NO2 has a ferromagnetic ground state that acts a half-metal. The half-metallic structure is verified by phonon dispersion and ab initio molecular dynamics simulations. Furthermore, the half-metallicity of Cr2NO2 is still robust when bias is applied to a nanometer-sized device, implying that the half-metallicity is intrinsic and does not require atomically clean surfaces. Therefore, the stable surface-oxygen-passivated MXene is a good candidate for spintronics.