Valley splitting in a van der Waals heterostructure WSe₂/CrI₃: A first-principles study

Atomically thin transition metal dichalcogenides (TMDs) have been considered as a wonderland for the research of valleytronics. Lifting the ±K valley degeneracy in TMDs has become an important research topic in the field of valleytronics. It is crucial to achieve large valley polarization for the development of valleytronics devices. In this work, we investigate the effects underpinning the ±K valley splitting in a van der Waals heterostructure WSe₂/CrI₃ based on first-principles calculations. We demonstrate that the stacking configuration affects the valley splitting dramatically and the influencing factors are discussed in details. The findings would further our basic understanding of the substrate effect on the valley degeneracy lifting in TMDs-based heterostructures beyond the WSe₂/CrI₃ and provide a useful guide to the valleytronic control in realistic applications.