Unveiling Spin-Dependent Polarization Dynamics of Interlayer Excitons in TMD-Based Heterostructures

Transition metal dichalcogenide (TMD) heterobilayers with type-II band alignment provide a versatile platform for spatially separating electrons and holes, facilitating the formation of interlayer excitons with distinct spin states. While these systems show great potential, the interaction between interlayer exciton spin states and polarization optics is not yet fully understood. Here, the manipulation of interlayer exciton linear polarization is reported in a WS₂/WSe₂ heterostructure integrated with low-symmetry antiferromagnetism CrOCl. This integration induces symmetry breaking, enabling the observation of spin-dependent polarization optical properties, as revealed by linearly polarized photoluminescence spectroscopy. The results show orthogonal optical anisotropy between spin-singlet and spin-triplet interlayer excitons under linearly polarized optical excitation. Additionally, magnetic field-dependent measurements reveal a polarization angle rotation driven by Berry curvature and geometric phase accumulation, demonstrating dynamic coupling between spin states and linear polarization. These findings advance the understanding of exciton spin dynamics and suggest a promising approach for leveraging spin-polarized optical properties in next-generation spintronic and polarization-sensitive optoelectronic devices.