p-orbital-dependent ferrovalley characteristic in MXene Lu3N2O2

Two-dimensional ferrovalley materials, which simultaneously exhibit ferromagnetism and valley polarization, have garnered substantial interest in recent years due to their fascinating physical properties and potential applications. However, the ferrovalley materials currently discovered are predominantly based on d orbitals. In this work, using first-principles calculations, we predict an exceptionally rare p-orbital-dependent ferrovalley characteristic in the MXene Lu3N2O2 monolayer. The monolayer shows intrinsic ferromagnetism contributed by the N-2p orbital with a magnetic moment of 1μB/u.c. Such 2p magnetism can be interpreted by the double exchange coupling between N anions mediated by the middle Lu cation. Owing to the simultaneous breaking of spatial inversion symmetry and time-reversal symmetry, the out-of-plane magnetization and spin–orbit coupling result in a sizable valley polarization of 80.93 meV in the conduction band for the monolayer. Notably, the energy dispersions that exhibit valley polarization are chiefly governed by the N-2p orbital, accompanied by a high Fermi velocity and a small effective electron mass. The demonstrated valley contrasting Berry curvature ensures that the monolayer can give rise to the anomalous valley Hall effect (AVHE) through electron doping, with the doping concentration evaluated in the range of 0.02–0.08 e/u.c. In addition to effectively modulating the magnitude of valley polarization, biaxial strain can also trigger the self-doping phenomenon, thereby enabling the monolayer to generate the AVHE independently of external electron doping. Our findings provide a more promising platform for valleytronic applications and significantly enrich the ferrovalley material family.