  One-dimensional Cr2NO2 nanoribbons cutting from the oxygen-passivated Cr2NO2
MXene are investigated by using density functional theory. The wide nanoribbons
have ferromagnetic ground states and are half-metals, independent of their
chirality. The half-metallic band gaps of the wide nanoribbons are larger than
1 eV, which are large enough for avoiding thermally activated spin flip. The
magnetism does not rely on the edge states but originates from all the Cr
atoms. Furthermore, the half-metallicity is still robust in an electronic
device even if the bias is up to 1 V. Therefore, one-dimensional Cr2NO2
nanoribbons are good candidates for spintronics.
