Regulation of the valleytronic properties in single-layer NbSeCl

The regulation of the valleytronic properties of two-dimensional materials can contribute to the in-depth study of valley physics and improve its potential for applications in valleytronic devices. Herein, we systematically investigate the electronic properties and the modulation of the valleytronic properties in single-layer NbSeCl. Our results reveal that NbSeCl is a semiconductor with a 105.2 meV valley splitting at K and K' valleys in the valence band. Magnetic doping and constructing heterostructures can significantly manipulate the valleytronic properties. Specifically, a large valley polarization of 79.5 meV can be induced by Cr atom doping, and the construction of heterostructures with HfN₂ can dramatically increase the valley splitting to 147.5 meV. Intriguingly, the type-II band alignment of the NbSeCl/HfN₂ heterostructure may extend the lifetime of valley excitons and realize the valley Hall effect in different layers by doping with electrons or holes.