Topological magneto-optical effects and their quantization in noncoplanar antiferromagnets
Topological magneto-optical effects and their quantization in noncoplanar antiferromagnets
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非共面反铁磁体中的拓扑磁光效应及其量化
DOI：
10.1038/s41467-019-13968-8
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发表时间：
2020-01-08
影响因子：
16.6
通讯作者：
Yao, Yugui
中科院分区：
文献类型：
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作者：
Feng, Wanxiang;Hanke, Jan-Philipp;Yao, Yugui
磁光效应反映了偏振光与磁性物质的基本相互作用，自世纪以来，磁光效应是众所周知的。这些现象的出现通常归因于磁体电子结构中交换劈裂和自旋轨道耦合之间的相互作用。利用理论论证，我们证明了拓扑磁光效应可以出现在非共面反铁磁体由于有限的标量自旋手征，没有任何参考交换分裂或自旋轨道耦合。我们提出了某些磁光量的光谱积分，揭示了所发现的效果的独特拓扑性质。我们还发现，克尔和法拉第旋转角可以量子化的绝缘拓扑反铁磁体在低频极限，由于非平凡的整体性质，体现在量子拓扑磁光效应。虽然预测的拓扑和量子拓扑磁光效应从根本上不同于传统的光-物质相互作用，它们可以通过现成的实验技术来测量。
Reflecting the fundamental interactions of polarized light with magnetic matter, magneto-optical effects are well known since more than a century. The emergence of these phenomena is commonly attributed to the interplay between exchange splitting and spin-orbit coupling in the electronic structure of magnets. Using theoretical arguments, we demonstrate that topological magneto-optical effects can arise in noncoplanar antiferromagnets due to the finite scalar spin chirality, without any reference to exchange splitting or spin-orbit coupling. We propose spectral integrals of certain magneto-optical quantities that uncover the unique topological nature of the discovered effect. We also find that the Kerr and Faraday rotation angles can be quantized in insulating topological antiferromagnets in the low-frequency limit, owing to nontrivial global properties that manifest in quantum topological magneto-optical effects. Although the predicted topological and quantum topological magneto-optical effects are fundamentally distinct from conventional light-matter interactions, they can be measured by readily available experimental techniques.