Cluster multipole theory for anomalous Hall effect in antiferromagnets
Cluster multipole theory for anomalous Hall effect in antiferromagnets
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DOI：
10.1103/physrevb.95.094406
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发表时间：
2016-11
影响因子：
3.7
通讯作者：
Michi-To Suzuki;T. Koretsune;M. Ochi;R. Arita
中科院分区：
文献类型：
--
作者：
Michi-To Suzuki;T. Koretsune;M. Ochi;R. Arita
在这里，作者发现了反铁磁性和霍尔效应之间缺失的联系，通过引入一个新的概念--团簇多极(CMP)来表征反铁磁体的宏观磁化强度。反常霍尔效应(AHE)通常是在铁磁体中观察到的，并被解释为宏观偶极磁化的结果，而CMP理论表明，在没有净磁化的情况下，某种类型的反铁磁(AFM)结构会导致AHE。新的序参数使我们能够表征AFM态的AHE，并解释了最近研究过的大的AHE的MnIr态和MnZ态($Z=Sn，Ge)的AHE。此外，该理论可以在与简单铁磁材料同等的基础上处理反铁磁体中的AHE。基于第一性原理计算，比较了反铁磁性Mn3Z和铁磁性体心立方Fe的AHE，找出了它们在CMP矩方面的相似之处。这一理论使我们目前对凝聚态中反常电流的理解向前迈进了一大步，所获得的知识可能对未来反铁磁器件的设计至关重要，例如，可能具有与自旋电子学相关的应用。
Here, the authors discover a missing link between antiferromagnetism and the Hall effect by introducing a theoretical framework based on a novel concept, cluster multipole (CMP), to characterize macroscopic magnetization of antiferromagnets. Whereas the anomalous Hall effect (AHE) is usually observed in ferromagnets and explained as an outcome of the macroscopic dipole magnetization, CMP theory reveals that a certain type of antiferromagnetic (AFM) structure induces the AHE despite no net magnetization. The new order parameters enable us to characterize the AHE in the AFM states and explain the AHE in the AFM states of Mn${}_{3}$Ir and Mn${}_{3}Z$ ($Z$ = Sn, Ge), for which the large AHE has recently been studied. Furthermore, the theory can deal with the AHE in antiferromagnets on an equal footing with that in simple ferromagnets. The authors compare the AHE in antiferromagnetic Mn${}_{3}Z$ Mn${}_{3}Z$ and ferromagnetic bcc Fe based on first-principles calculations and find out their similarity with respect to the CMP moments. The theory brings on a significant step forward in our current understanding of anomalous current in condensed matter, and the obtained knowledge could be crucial in the future for the design of antiferromagnetic devices, e.g., with possible spintronics-related applications.