近日，美国华盛顿大学Xu, Xiaodong团队研究了整数和分数陈氏绝缘子的光学控制。相关论文于2026年1月28日发表在《自然》杂志上。

拓扑结构的光学调控研究，尤其在电子关联效应存在的体系中，是一项具有广泛科学与技术影响力的重要课题。 扭转二碲化钼双层结构（tMoTe₂）是一种零磁场下的分数量子陈绝缘体（FCI），展现出分数量子化的反常霍尔效应。由于边缘态的手性和陈数的符号由其基底的铁磁极化决定，调控铁磁性将实现对陈绝缘体（CI）/FCI态的控制。

研究组通过圆偏振光泵浦在tMoTe₂中实现了对铁磁极化，进而对CI态和FCI态的光学调控。在低激发功率下，他们通过"光学训练"实现了铁磁极化的按需制备：即在旋光选择性光泵浦下，通过电学调控将体系从非铁磁态切换至所需的铁磁态。在更高激发功率下，研究组进一步实现了远低于居里温度时铁磁极化的直接光学翻转。

光学训练与直接翻转在CI和FCI态附近最为有效，这归因于光泵穴的能隙增强型谷极化。通过调制激发光的旋向，磁化状态可实现动态切换。空间分辨测量进一步展示了铁磁畴（即CI或FCI畴）的光学写入能力。该工作实现了对拓扑量子多体体系的精确光学调控，为拓扑自旋电子学、量子存储器，以及通过可编程的整数与分数量子化反常霍尔畴图案构建新奇边缘态等潜在应用奠定了基础。

附：英文原文

Title: Optical control of integer and fractional Chern insulators

Author: Holtzmann, William, Li, Weijie, Anderson, Eric, Cai, Jiaqi, Park, Heonjoon, Hu, Chaowei, Taniguchi, Takashi, Watanabe, Kenji, Chu, Jiun-Haw, Xiao, Di, Cao, Ting, Xu, Xiaodong

Issue&Volume: 2026-01-28

Abstract: Optical control of topology, particularly in the presence of electron correlations, is an interesting topic with broad scientific and technological impact1,2,3,4. Twisted MoTe2 bilayer (tMoTe2) is a zero-field fractional Chern insulator (FCI)5,6,7,8,9,10, exhibiting the fractionally quantized anomalous Hall effect11,12,13,14. As the chirality of the edge states and sign of the Chern number are determined by the underlying ferromagnetic polarization15,16, manipulation of ferromagnetism would realize control of the Chern insulator (CI)/FCI states. Here we demonstrate control of ferromagnetic polarization, and thus the CI and FCI states, by circularly polarized optical pumping in tMoTe2. At low excitation power, we achieve on-demand preparation of ferromagnetic polarization by optical training, that is, electrically tuning the system from non-ferromagnetic to desirable ferromagnetic states under helicity-selective optical pumping. With increased excitation power, we further realize direct optical switching of ferromagnetic polarization at a temperature far below the Curie temperature17,18. Both optical training and direct switching are most effective near CI and FCI states, which we attribute to a gap-enhanced valley polarization of optically pumped holes. The magnetization can be dynamically switched by modulating the helicity of optical excitation. Spatially resolved measurements further demonstrate optical writing of ferromagnetic, and thus CI (or FCI) domains. Our work realizes precise optical control of a topological quantum many-body system with potential applications in topological spintronics, quantum memories and creation of exotic edge states by programmable patterning of integer and fractionally quantized anomalous Hall domains4,19.

DOI: 10.1038/s41586-025-09777-3

Source: https://www.nature.com/articles/s41586-025-09777-3