Year: 2026
Type: preprint
Abstract: The interaction between plasmons and magnons is a long-sought phenomenon with implications for fundamental physics and spintronics applications. In three-dimensional systems, this coupling is suppressed by the large mismatch in energy scales, but two-dimensional (2D) plasmons with gapless dispersion can overlap with magnons over a broad spectral range. Despite numerous theoretical predictions, experimental observation of magnon-plasmon interaction has remained elusive. In this work, we study a first-of-its-kind hybrid plasmon-magnon platform based on 2D materials. By deploying scattering-type scanning near-field optical microscopy (s-SNOM) with terahertz radiation, we image propagating plasmon wavepackets at a graphene/NiPS$_3$ interface and track their dynamics across the antiferromagnetic transition of NiPS$_3$. We observe a clear renormalization of the plasmon-polariton dispersion concurrent with the onset of antiferromagnetic order. With complementary Raman scattering and nano-terahertz spectroscopy, we unveil spectral weight redistribution and dielectric screening changes, potentially associated with the multi-magnon continuum, as the underlying mechanism. These results provide solid evidence of coupling between plasmon and antiferromagnetic order, marking a cornerstone for a potential platform for hybrid magnon-plasmon interactions in 2D materials, opening avenues for coherent spin-plasmon devices and tunable terahertz spintronic components.
Source: arXiv (Cornell University)
Authors: Su, Yifan, Xu, Suheng, Vitalone, Rocco A., Liu, Ziyu, Boström, Emil Viñas, Wu, Na, Huang, Chun-Ying, Zhang, Zhuquan, Jung, Jaehoon, Chica, Daniel G., Avelar, Vinícius da Silveira Lan, Wang, Yiping, Taniguchi, Takashi, Watanabe, Kenji, Hone, James C., Zhu, Xiaoyang, Dean, Cory R., Roy, Xavier, Rubio, Angel, Basov, D. N.
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7208705992
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