Unveiling the spin evolution in van der Waals antiferromagnets via magneto-exciton effects

• Published in: Nature communications Vol. 15; no. 1; pp. 8011 - 9
• Main Authors: Wang, Xingzhi, Tan, Qishuo, Li, Tie, Lu, Zhengguang, Cao, Jun, Ge, Yanan, Zhao, Lili, Tang, Jing, Kitadai, Hikari, Guo, Mingda, Li, Yun-Mei, Xu, Weigao, Cheng, Ran, Smirnov, Dmitry, Ling, Xi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.09.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 140/125; 639/301/1019; 639/301/119; Antiferromagnetism; Coupling; Emission; Emissions; Excitons; Humanities and Social Sciences; Magnetic fields; Magnetism; Magnets; multidisciplinary; Optics; Polarization (spin alignment); Science; Science (multidisciplinary); Spin structure; Splitting
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-51643-9

Among the fascinating phenomena observed in two-dimensional (2D) magnets, the magneto-exciton effect stands out as a pivotal link between optics and magnetism. Although the excitonic effect has been revealed and exhibits a considerable correlation with the spin structures in certain 2D magnets, the underlying mechanism of the magneto-exciton effect remains underexplored, especially under high magnetic fields. Here we perform a systematic investigation of the spin-exciton coupling in 2D antiferromagnetic NiPS 3 under high magnetic fields. When an in-plane magnetic field is applied, the exceptional sharp excitonic emission at ~1.4756 eV exhibits a Zeeman-like splitting with g  ≈ 2.0, experimentally identifying the exciton as an excitation of dominant triplet-singlet character. By examining the polarization of excitonic emission and simulating the spin evolution, we further verify the correlation between excitonic emission and Néel vector in NiPS 3 . Our work elucidates the mechanism behind the spin-exciton coupling in NiPS 3 and establishes a strategy for optically probing the spin evolutions in 2D magnets. NiPS 3 , a van der Waals antiferromagnet exhibits exciton emission with a very sharp linewidth. The exact origin of this is has been a subject of active debate. Here, Wang et al study the behavior of this sharp exciton peak under applied magnetic fields, and find a Zeeman-like splitting, indicating the exciton has triplet-singlet character.