Magnon hydrodynamics in an atomically thin ferromagnet

• 成果类型: Article
• 署名作者: Xue, Ruolan; Maksimovic, Nikola; Dolgirev, Pavel E.; Xia, Li-Qiao; Muller, Aaron; Kitagawa, Ryota; Machado, Francisco; Klein, Dahlia R.; MacNeill, David; Watanabe, Kenji; Taniguchi, Takashi; Jarillo-Herrero, Pablo; Lukin, Mikhail D.; Demler, Eugene; Yacoby, Amir
• 署名单位: Harvard University; Harvard University; Massachusetts Institute of Technology (MIT); Institute of Science Tokyo; Tokyo Institute of Technology; Smithsonian Institution; Harvard University; Smithsonian Astrophysical Observatory; Weizmann Institute of Science; National Institute for Materials Science
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8075; 1095-9203
• DOI: 10.1126/science.adp2397
• 发表日期: 2026-05-21
• 页码: 873-878
• 关键词: EQUILIBRIUM NOISE; electron; resistance; vortices; spectrum; heat; FLOW

摘要

Strong interactions between particles can lead to emergent collective excitations. Spin waves, known as magnons, have been predicted to reach a strongly interacting hydrodynamic regime, where they form a slow collective density mode. In this work, we isolate exfoliated sheets of chromium trichloride (CrCl3), where magnon interactions are strong, and develop a technique to measure the collective magnon dynamics though nearby nitrogen-vacancy centers in diamond. Thermal magnetic fluctuations generated by monolayer CrCl3 increase upon decreasing temperature; this anomalous trend may be a consequence of the damping rate of a low-energy magnon sound mode that sharpens as magnon interactions increase with increasing temperature. By measuring the magnetic fluctuations emitted by thin multilayer CrCl3 in the presence of a variable-frequency drive field, we obtain spectroscopic evidence for this two-dimensional magnon sound mode.