Strain‐Induced Ferromagnetism and Valley Polarization Enhancement in WSe ₂ /WSe ₂ /NiPS ₃ Moiré Superlattices

Moiré superlattices, formed by stacking layered materials with slight lattice mismatches or rotational misalignment, provide a powerful platform for engineering quantum states at the nanoscale. These systems enable precise control over exciton dynamics and correlated electronic phases through the moiré potential. While significant progress has been made in understanding moiré excitons in twisted bilayer systems, their integration with magnetic materials for tunable excitonic control remains challenging. Here, a heterostructure comprising twisted bilayer WSe₂ and the antiferromagnet NiPS₃ is investigated, placed on an optical microcavity with silicon holes. Low-temperature photoluminescence (PL) measurements reveal that the microcavity edge enhances both the PL intensity and optical anisotropy of moiré excitons. Additionally, strain modulation at the microcavity edge alters the magnetic ordering of NiPS₃ and significantly enhances the valley polarization under an external magnetic field. These findings demonstrate a robust approach for integrating magnetic order with moiré superlattices, offering new avenues for controlling exciton properties in quantum information and photonic applications.