近日，美国哈佛大学Amir Yacoby团队报道了原子薄铁磁体中的磁振子流体力学。相关论文于2026年5月21日发表在《科学》杂志上。

粒子间的强相互作用可导致涌现的集体激发。自旋波（即磁子）被预言会进入一个强相互作用的流体动力学区域，在此区域中形成慢速的集体密度模式。

在该工作中，研究组分离出三氯化铬（CrCl₃）的剥离薄片（该材料中磁子相互作用很强），并发展了一种技术，利用金刚石中附近的氮-空位中心来测量集体磁子动力学。单层CrCl₃产生的热磁涨落随温度降低而增加；这一反常趋势可能源于低能磁子声学模式的阻尼率——随着温度升高、磁子相互作用增强，该模式会变得尖锐。通过测量薄层多层CrCl₃在变频驱动场存在下发射的磁涨落，研究组获得了这种二维磁子声学模式的光谱学证据。

附：英文原文

Title: Magnon hydrodynamics in an atomically thin ferromagnet

Author: Ruolan Xue, Nikola Maksimovic, Pavel E. Dolgirev, Li-Qiao Xia, Aaron Müller, Ryota Kitagawa, Francisco Machado, Dahlia R. Klein, David MacNeill, Kenji Watanabe, Takashi Taniguchi, Pablo Jarillo-Herrero, Mikhail D. Lukin, Eugene Demler, Amir Yacoby

Issue&Volume: 2026-05-21

Abstract: 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.

DOI: adp2397

Source: https://www.science.org/doi/10.1126/science.adp2397