发表机构
Physikalisches Institut, Universität Stuttgart; Max Planck Institute for Chemical Physics of Solids; National High Magnetic Field Laboratory, Florida State University（斯图加特大学第一物理研究所; 马克斯·普朗克固体化学物理研究所; 佛罗里达州立大学国家高磁场实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过光学光谱和DFT计算证明电子关联主导Mn$_3$Sn和Mn$_3$Ge的低能光学响应，提出关联修正的能带结构解释，为关联拓扑金属研究提供模板。
AI 中文摘要
利用光学光谱和密度泛函理论，我们提供证据表明电子-电子相互作用强烈影响kagome反铁磁体Mn$_3$Sn的性质，因为其低能光学带间跃迁完全源于关联修正的电子能带结构。Mn$_3$Sn的光学有效质量约为其同构类似物Mn$_3$Ge的三倍。采用Lichtenstein公式中的DFT+$U$处理，在位库仑排斥$U = 4$~eV和Hund耦合$J = 0.25$~eV，可以解释Mn$_3$Sn的光学跃迁，而Mn$_3$Ge的光学跃迁在无Hubbard修正（$U, J = 0$）时已被再现。Mn$_3$Sn的近各向同性电子结构揭示了一种三维金属，其电子响应主要由Mn $d$态塑造。在Mn$_3$Sn和Mn$_3$Ge中观察到的$\sigma_1(\omega)$表观线性区域源于多个重叠的带间跃迁，因此不应被解释为Weyl锥的光学特征。光学响应在高达17 T的磁场下不改变，与强自由载流子屏蔽一致。我们的发现建立了Mn$_3$Sn和Mn$_3$Ge的全面关联图像，为其他关联拓扑金属提供了模板。
英文摘要
Using optical spectroscopy and density functional theory, we provide evidence that electron-electron interactions strongly affect the properties of the kagome antiferromagnet Mn$_3$Sn, since its low-energy optical interband transitions arise exclusively from the correlation-modified electronic band structure. Mn$_3$Sn possesses an optical effective mass about three times larger than that of its isostructural analog Mn$_3$Ge. The DFT+$U$ treatment in the Lichtenstein formulation, with an on-site Coulomb repulsion $U = 4$~eV and Hund's coupling $J = 0.25$~eV, accounts for the optical transitions in Mn$_3$Sn, whereas those in Mn$_3$Ge are already reproduced without Hubbard corrections ($U, J = 0$). The near-isotropic electronic structure of Mn$_3$Sn reveals a three-dimensional metal whose electronic response is shaped prominently by the Mn $d$-states. The apparent linear regime in $σ_1(ω)$ observed in Mn$_3$Sn and Mn$_3$Ge arises from several overlapping interband transitions and therefore should not be interpreted as the optical signature of the Weyl cones. The optical response does not alter with magnetic field up to 17 T, consistent with strong free-carrier screening. Our findings establish a comprehensive-correlated picture of Mn$_3$Sn and Mn$_3$Ge that offers a template for other correlated topological metals.
