Photo-Tunable Magnetoresistance and Resistivity Crossover in 2D Antiferromagnet CrSBr

We report a comprehensive study of magnetotransport in few-layer van der Waals antiferromagnet CrSBr, revealing how optical illumination profoundly alters its magnetic and electronic behavior. A temperature-dependent resistivity crossover appearsnear the Néel temperature (∼ 132 K), marking transitions from phonon-limited conduction at high temperatures to magnon-assisted localization and, finally, hopping conductivity in the low-temperature insulating phase. Below the Néel temperature, illumination dramatically enhances negative magnetoresistance, evidencing a strong coupling between photoexcited carriers and magnetic order. Notably, linearly polarized light induces an anisotropic magnetoresistance response, whereas circularly polarized light yields an isotropic effect, reflecting the role of crystal anisotropy in photo magneto-transport. These findings demonstrate light-controlled modulation of the resistance and magnetic order in CrSBr, underscoring its promise for opto-magnetoelectronic and spintronic applications based on van der Waals antiferromagnets.