发表机构
Joint Quantum Institute, University of Maryland; Max Planck Institute for the Structure and Dynamics of Matter（马里兰大学联合量子研究所; 马克斯·普朗克物质结构动力学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文利用双磁子拉曼散射在范德华反铁磁体CrSBr中首次直接探测层间自旋关联，与无拟合参数的自旋波模型高度吻合，并发展了激子增强变体技术，为二维磁性研究开辟了新窗口。
AI 中文摘要
自旋关联调控着量子材料的众多集体行为，支撑着非常规超导和拓扑磁性等奇异现象。在层状材料中，层间自旋关联至关重要，因为它表征了磁性基态并决定了界面间的自旋输运。然而，层间自旋关联一直难以直接测量，使得二维磁性最基本的物理量之一无法通过实验触及。在此，我们利用范德华反铁磁体（AFM）CrSBr中的双磁子拉曼散射，首次实现了对层间自旋关联的直接光学探测，实验结果与无任何拟合参数的微观自旋波模型高度吻合。此外，双磁子通道仅在反铁磁态下开启，当磁场将晶体转变为铁磁态时，该通道消失。我们还进一步建立了一种激子介导的变体技术，即将激光调谐至激子共振附近时，由于激子具有大的振子强度，信号增强了约十倍。因此，磁子对拉曼光谱学为范德华磁体中的层间自旋关联开辟了直接的光学窗口，并可推广至扭转双层和邻近耦合异质结构。
英文摘要
Spin correlations govern numerous collective behaviors of quantum materials, underpinning exotic phenomena such as unconventional superconductivity and topological magnetism. In layered materials, the interlayer spin correlation is important because it characterizes the magnetic ground state and determines spin transport across the interface. Yet interlayer spin correlations have remained hard to measure directly, leaving one of the most basic quantities of two-dimensional magnetism out of experimental reach. Here we provide the first direct optical probe of interlayer spin correlations, using two-magnon Raman scattering in the van der Waals antiferromagnet (AFM) CrSBr, in remarkable agreement with a microscopic spin-wave model without any fitting parameter. Moreover, the two-magnon channel switches on only in the AFM state and vanishes when a magnetic field takes the crystal to a ferromagnetic state. We furthermore establish an exciton-mediated variant of the technique, where tuning the laser near the exciton resonance enhances the signal roughly tenfold due to the exciton's large oscillator strength. Magnon-pair Raman spectroscopy thus opens a direct optical window into interlayer spin correlations in van der Waals magnets, extendable to twisted bilayers and proximity-coupled heterostructures.
Comments27 pages, 4 figures (main text), 7 supplementary figures, 1 supplementary table. Includes Supplementary Information
