Magnetic tuning of optical anisotropy in 2D materials: Insights from antiferromagnetic-TMDC interfaces

Atomically thin two-dimensional (2D) magnetic materials offer unique opportunities to enhance interactions between electron spin, charge, and lattice, leading to novel physical properties at low-dimensional scales. While extensive research has explored how breaking three-fold (C₃) rotational symmetry in transition metal dichalcogenides (TMDC) can induce optical anisotropy at heterointerfaces, the role of magnetism in modulating these anisotropic optical properties remains underexplored. Here, we engineer an antiferromagnet/semiconductor heterostructure by coupling isotropic MoWSe₂ with the low-symmetric antiferromagnet NiPS₃, introducing in-plane anisotropy in the MoWSe₂ alloy. Low-temperature photoluminescence (PL) measurements reveal a pronounced linear polarization-dependent exciton emission intensity at the MoWSe₂/NiPS₃ interface, with anisotropy ratios of 1.09 and 1.07 for charged and neutral excitons, respectively. Furthermore, applying an out-of-plane magnetic field results in a dramatic rotation of the exciton polarization direction by up to 90° at 9 T, significantly exceeding the previously reported maximum deflection of around 27°. This pronounced polarization rotation is not solely attributed to valley coherence, indicating a strong influence of the magnetic order in NiPS₃. These findings provide new insights into the role of magnetic ordering in tuning optical anisotropy in 2D materials, paving the way for the development of advanced polarization-sensitive optoelectronic and magneto-optic devices.