Valley polarization and magnetic anisotropy of two-dimensional NiClI/MoSe heterostructures.

Two-dimensional (2D) Janus trihalides have attracted widespread attention due to their potential applications in spintronics. In this work, the valley polarization of MoSe at the K' and K points can be modulated by NiClI, a new 2D Janus trihalide. The NiClI/MoSe heterostructure has an in-plane magnetic anisotropy energy (IMA) and is characterized by three distinct electronic structures: metallic, semiconducting, and half-metallic. It is noted that the semiconducting state features a band gap of 0.07 eV. When spin-orbit coupling (SOC) is considered, valley polarization is exhibited in the NiClI/MoSe heterostructure, with the degree of valley polarization varying across different configurations and reaching a maximum value of 4.6 meV. The electronic properties, valley polarization and MAE of the system can be tuned by biaxial strains. The application of a biaxial strain ranging from -6% to +6% can enhance the valley polarization value from 0.9 meV to 12.9 meV. The directions of MAE of the NiClI/MoSe heterostructure can be changed at biaxial strains of -6%, +2%, +4% and +6%. The above calculation results show that the heterostructure system possesses rich electronic properties and tunability, with extensive potential applications in the fields of spintronic and valleytronic devices.