近日，美国斯坦福大学Eylon Persky团队研究了魔角扭曲双层石墨烯轨道磁性的光学控制。2026年1月6日出版的《自然—物理学》杂志发表了这项成果。

扭曲石墨烯结构中的平带承载着各种强关联和拓扑现象。对其进行光学探测和控制可以揭示对称性和动力学等重要信息，但由于与光学波长相比能隙较小，这一直是一项挑战。

研究组报告了在单层WSe2器件上的魔角扭曲双层石墨烯中，轨道磁性及相关反常霍尔效应的近红外光学控制。他们展示了利用圆偏振光控制整数莫尔填充附近反常霍尔效应的滞后现象和幅度。通过调制光的螺旋性，研究组在宽范围的填充下观察到横向电阻的周期性调制，这表明光通过大的逆法拉第效应诱导了轨道磁化。在金属态和反常霍尔效应状态之间的过渡区，研究组还揭示了霍尔电阻率的大幅度随机切换，他们认为这是由光调谐的磁畴渗透簇引起的。该结果表明了光学操纵莫尔结构中关联性和拓扑性的潜力。

附：英文原文

Title: Optical control of orbital magnetism in magic-angle twisted bilayer graphene

Author: Persky, Eylon, Parisot, Lonie, He, Minhao, Cai, Jiaqi, Taniguchi, Takashi, Watanabe, Kenji, May-Mann, Julian, Xu, Xiaodong, Kapitulnik, Aharon

Issue&Volume: 2026-01-06

Abstract: Flat bands in twisted graphene structures host various strongly correlated and topological phenomena. Optically probing and controlling them can reveal important information such as symmetry and dynamics, but this has been challenging due to the small energy gap compared with optical wavelengths. Here we report on the near-infrared optical control of orbital magnetism and associated anomalous Hall effects in a magic-angle twisted bilayer graphene on a monolayer WSe2 device. We demonstrate control over the hysteresis and amplitude of the anomalous Hall effect near integer moiré fillings using circularly polarized light. By modulating the light helicity, we observe periodic modulation of the transverse resistance in a wide range of fillings, indicating light-induced orbital magnetization through a large inverse Faraday effect. At the transition between metallic and anomalous Hall effect regimes, we also reveal large and random switching of the Hall resistivity, which we attribute to the light-tuned percolating cluster of magnetic domains. Our results demonstrate the potential of the optical manipulation of correlation and topology in moiré structures.

DOI: 10.1038/s41567-025-03117-y

Source: https://www.nature.com/articles/s41567-025-03117-y