In‐Plane Quantum Anomalous Hall Effect in Ferromagnetic Type‐I Nodal Line Semimetal of Monolayer YbN

The monolayer YbN is predicted to be a 2D nodal line semimetal with full spin polarization in the absence of spin–orbit coupling as well as an intrinsic ferromagnet with an easy magnetic xy plane and T c = 85 K. Considering the spin–orbit coupling with magnetic moments along z direction, the band crossings near Fermi level around Γ points are still preserved and robust against spin–orbit coupling. On the contrary, when the spin–orbit coupling is considered with magnetic moments oriented in‐plane along x and y directions, the band crossings are broken, and the bandgap of the magnetic moment along the y direction is larger than that in the x direction, which results in topologically nontrivial insulating property. The anomalous Hall conductivity calculations show the Chern number C = −1, implying the existence of one edge state in the finite‐width nanoribbon. The findings provide ideal candidates for investigating the design of electronic devices related to 2D nontrivial magnetic materials.