Giant Circularly Polarized Emission in NiPS₃/WSe₂ 2D Heterostructures

The recent interest in magnetic two-dimensional (2D) van der Waals (vdW) materials changed paradigms in science and technology, unveiling novel physical phenomena such as valleytronics, spin selectivity, and quantum effects. These 2D materials possess nearly atomically thin layers with strong intralayer bonding but weak vdW interlayer coupling, while metals within the plane are organized in a honeycomb lattice. The weak vdW forces enable the separation of a single or a few layers by micromechanical or chemical exfoliation. Furthermore, the formation of vdW heterostructures (HSs) through stacking dissimilar layers offers unprecedented functionalities beyond those of individual components.<br/>This study investigates the electronic and optical characteristics of HSs composed of NiPS₃ and Wse₂. NiPS₃, an antiferromagnetic material, and WSe₂, known for its spin-valley features, exhibit a quasi-type II band alignment when coupled. Magneto photoluminescent (PL) measurements reveal substantial alterations in polarization behavior under external magnetic fields, achieving up to 80% circular polarization at -8 Tesla and 45% at 0 Tesla, indicative of a Rashba effect induced by spin-orbit coupling. Circularly polarized PL measurements further unveil energy band splitting arising from spin and valley interactions, highlighting potential applications in quantum and photo-spintronic devices. These findings underscore the mutual interaction between magnetic and optical properties in HSs, offering new insights for future research in material science and device applications.