Engineering polarization anisotropy in WSe2/CrOCl heterostructures via magnetic and strain effects

Abstract

Two-dimensional transition metal dichalcogenides show potential for optoelectronic applications owing to their exceptional excitonic properties. While optical anisotropy driven by symmetry breaking has been extensively studied, the combined effects of magnetism and strain on anisotropy remain less explored. Here, we engineer heterostructures by integrating isotropic monolayer WSe2 with low-symmetry antiferromagnetic CrOCl and depositing them onto Au nanopillar arrays, effectively introducing optical anisotropy into WSe2. Polarization-resolved PL measurements at both room temperature (300 K) and cryogenic conditions (1.7 K) demonstrate strong region-dependent anisotropies induced along distinct axes by strain and CrOCl. Application of out-of-plane magnetic fields (±9 T) induces opposing modulation of anisotropy in strained and unstrained regions—enhancing and suppressing excitonic polarization by 30.38% and 30.3%, respectively. Temperature-dependent studies further reveal tunable anisotropy up to 23.08%, indicating the interplay of magnetic and thermal effects under strain. First-principles calculations suggest anisotropy via redistribution of the in-plane charge density in WSe2 induced by CrOCl. This work provides insights into the customization and active control of the anisotropic optical phenomena in two-dimensional heterostructures, enabling polarization-sensitive optoelectronic and spintronic applications.