Ren Shuliang, Pang Simin, Guan Shan, Sun Yu-Jia, Zhang Tian-Yu, Jiang Nai, Guo Jiaqi, Zheng Houzhi, Luo Jun-Wei, Tan Ping-Heng, Shen Chao, Zhang Jun
State Key Laboratory of Semiconductor Physics and Chip Technologies, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
Nano Lett. 2025 Feb 19;25(7):2709-2715. doi: 10.1021/acs.nanolett.4c05724. Epub 2025 Feb 6.
Broken symmetry plays a pivotal role in determining the macroscopic electrical, optical, magnetic, and topological properties of materials. Circular dichroism (CD) has been widely employed to probe broken symmetry in various systems, from small molecules to bulk crystals, but designing CD responses on demand remains a challenge, especially for antiferromagnetic materials. Here we develop a cavity-enhanced CD technique to sensitively probe the magnetic order and broken symmetry in the van der Waals antiferromagnet FePS. By introducing interfacial inversion asymmetry in cavity-coupled FePS crystals, we demonstrate that the induced CD is strongly coupled with the zigzag antiferromagnetic order of FePS and can be tuned both spectrally and in magnitude by varying the cavity length (FePS thickness). Our findings open new avenues for using cavity-modulated CD as a sensitive diagnostic probe to detect weak broken symmetries, particularly at hidden interfaces, and in systems exhibiting hidden spin polarization or strong correlations.
破缺对称性在决定材料的宏观电学、光学、磁学和拓扑性质方面起着关键作用。圆二色性（CD）已被广泛用于探测从小分子到块状晶体等各种体系中的破缺对称性，但按需设计CD响应仍然是一个挑战，特别是对于反铁磁材料。在此，我们开发了一种腔增强CD技术，以灵敏地探测范德华反铁磁体FePS中的磁序和破缺对称性。通过在腔耦合FePS晶体中引入界面反转不对称性，我们证明诱导的CD与FePS的锯齿形反铁磁序强烈耦合，并且可以通过改变腔长（FePS厚度）在光谱和幅度上进行调节。我们的发现为利用腔调制CD作为灵敏的诊断探针来检测弱破缺对称性开辟了新途径，特别是在隐藏界面以及表现出隐藏自旋极化或强关联的体系中。
