Magneto-Polarization Controlled by Intervalley Scattering of Interlayer Excitons and Carriers in WS₂/WSe₂ Heterostructure

The photoluminescence polarization of interlayer excitons (IXs) offers a powerful tool for exploring moiré physics of transition metal dichalcogenide (TMD) heterostructures. However, in WS₂/WSe₂ heterostructures, this polarization is often weak and the underlying mechanism of intervalley scattering remains unclear. Notably, the closeness of IX lifetime and carrier valley lifetime complicates the investigation of the scattering process. Here, we demonstrate that magnetic fields can sensitively tune the polarization and valley dynamics of both IX and carriers in WS₂/WSe₂ heterostructures. We find that small magnetic fields can suppress IX intervalley scattering, significantly enhancing valley polarization, whereas at higher magnetic fields, IX emission is largely controlled by the intervalley scattering of electrons, leading to excitation-dependent polarization and saturation effects. Our results highlight the interplay between carrier dynamics and exciton valley behaviors in tailoring IX photoluminescence and offering potential pathways for the design of valleytronic devices leveraging TMD heterostructures.