Synergistic Magnetic and Thermal Tuning of Excitonic Anisotropy in 2D Ferroelectric Heterostructures

Two-dimensional transition metal dichalcogenides (TMDCs) are promising materials for next-generation optoelectronic technologies due to their strong excitonic effects. While optical anisotropy arising from symmetry breaking has been extensively studied, the combined influence of magnetic fields, layer thickness, and temperature on the anisotropy remains poorly understood. Here, we engineer optical anisotropy in isotropic WSe 2 monolayers by integrating them with low-symmetry ferroelectric CuInP 2 S 6 (CIPS) on Si/SiO 2 substrates. Polarization-resolved photoluminescence measurements reveal layer-dependent magnitudes and orientations of anisotropy in CIPS, which persist from room temperature (300 K) to cryogenic conditions (1.7 K). Under magnetic fields ranging from −9 to 9 T, the excitonic anisotropy can be reversibly modulated by up to 18.19% and 40.71% across different heterostructure regions. Temperature variation further enhances this tunability, enabling anisotropy modulation of up to 47.37% and 71.68%. First-principles calculations attribute these effects to CIPS-induced in-plane charge redistribution in WSe 2, establishing a microscopic origin for the observed anisotropy. Our results reveal a synergistic interplay among magnetic, thermal, and structural degrees of freedom, providing a pathway for designing actively tunable, polarization-sensitive optoelectronic and spintronic devices based on two-dimensional ferroelectric heterostructures.