Photo-induced anomalous Hall effect in Co/WS2 bilayer

Abstract

We report the observation of a photo-induced anomalous Hall effect in a ferromagnetic (FM) cobalt (Co)/tungsten disulfide (WS2) Schottky heterostructure. Unlike previously reported transition metal dichalcogenides (TMDCs)-based devices that rely on circularly polarized light or external polarization fields, our FM/TMDC interface generates a transverse Hall voltage under unpolarized illumination, eliminating the need for complex optical configurations. Upon illumination, photocarriers created in the WS2 layer diffuse into the FM Co layer and experience a Lorentz force under an in-plane magnetic field, producing a transverse open-circuit voltage. The voltage scales linearly with optical power but exhibits a nonlinear, hysteretic dependence on magnetic-field strength, reflecting spin-dependent scattering in the FM Co layer. The photo-induced voltage reproduces the magneto-optical Kerr hysteresis loop, enabling reconstruction of in-plane magnetic hysteresis using only optical excitation and two electrical contacts. These findings introduce a simple and efficient platform for optical and magnetic sensing based on FM/TMDC Schottky interfaces.