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.本研究针对少层范德华（van der Waals）反铁磁体CrSBr的磁输运行为开展了系统性探究，揭示了光辐照如何显著改变其磁学与电学特性。该体系在奈尔温度（Néel temperature，~132 K）附近出现与温度相关的电阻率交叉行为，标志着输运机制从高温下的声子限制输运（phonon-limited conduction），逐步过渡至磁振子辅助局域化（magnon-assisted localization），最终进入低温绝缘相中的跳跃电导（hopping conductivity）模式。在奈尔温度以下，光辐照可显著增强负磁阻（negative magnetoresistance）效应，表明光激发载流子（photoexcited carriers）与磁序之间存在强耦合作用。值得注意的是，线偏振光（linearly polarized light）可诱导各向异性磁阻（anisotropic magnetoresistance）响应，而圆偏振光（circularly polarized light）则产生各向同性效应（isotropic effect），这反映了晶体各向异性在光磁输运过程中的作用。上述研究结果证实了CrSBr中可通过光控方式调控电阻率与磁序，凸显了其在基于范德华反铁磁体的光磁电子（opto-magnetoelectronic）与自旋电子学（spintronic）应用中的巨大潜力。