磁性外尔半金属Co₃Sn₂S₂中的太赫兹反常霍尔效应
Terahertz anomalous Hall effect in magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$
AI总结：
本研究结合太赫兹光谱与半解析计算，系统研究磁性外尔半金属Co₃Sn₂S₂的低能旋光光学响应，解释其磁光现象并约束材料参数。
AI中文摘要：
已知时间反演对称性破缺的外尔半金属，其电子能带结构中至少存在两个在动量空间分离的节点，这些节点作为贝里曲率的源与汇，会产生被称为反常霍尔效应（AHE）的横向霍尔电导率。在最简单的双节点图像中，零频率极限下的反常霍尔效应与节点间的动量空间分离度成正比。在近期发现的外尔半金属Co₃Sn₂S₂中，已观测到巨大的反常霍尔效应，但针对低能区域（可直接探测外尔节点附近准粒子激发）的实验研究仍较为有限。本研究结合太赫兹光谱与基于物理直觉有效模型的半解析计算，对Co₃Sn₂S₂的本征低能旋光光学响应开展系统研究。研究结果从外尔节点动量空间分离产生的本征旋光性出发，为观测到的磁光现象提供了可靠且清晰的解释；实验与理论的定量对比，也为该材料的参数设定了严格约束。
英文摘要：
Time-reversal-symmetry-broken Weyl semimetals are known to have at least two nodes in their electronic band structure, separated in momentum space and acting as sources and sinks of Berry curvature. This gives rise to a transverse Hall conductivity, known as the anomalous Hall effect (AHE), which, in the simplest two-node picture, is proportional to the momentum-space separation between the nodes in the zero frequency limit. In the recently discovered Weyl semimetal $\mathrm{Co_3Sn_2S_2}$, a giant AHE has been observed. However, experimental investigations in the low-energy regime, which directly probe quasiparticle excitations near the Weyl nodes, remain limited. Here, we present a systematic study of the intrinsic low-energy gyrotropic optical response of $\mathrm{Co_3Sn_2S_2}$ using terahertz spectroscopy combined with semianalytical calculations based on a physically intuitive effective model. Our results provide a robust and transparent explanation of the observed magnetooptical phenomena in terms of intrinsic gyrotropy arising from momentum-space separation of the Weyl nodes. Furthermore, quantitative comparison between experiment and theory places stringent constraints on the material parameters.
