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arXiv 1701.03030cond-mat.mtrl-sci
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反铁磁Skyrmions中的拓扑自旋霍尔效应

Topological spin Hall effect in antiferromagnetic skyrmions

Patrick M. Buhl, Frank Freimuth, Stefan Blügel, Yuriy Mokrousov

摘要:

拓扑霍尔效应(THE)是手性Skyrmion晶格非平凡拓扑的主要表现形式之一,传统上被用来探测具有局部铁磁序的Skyrmion晶格的出现。在这项工作中,我们证明了非平凡的二维手征纹理的外观与本地{ \it反}-铁磁顺序可以通过$-$的自旋版本的拓扑自旋霍尔效应(TSHE)检测。利用半经典的形式主义,这里用来结合手征反铁磁纹理的共线,简并电子结构的密度泛函理论描述,我们遵循的电子SU(2)波包在外部电场的实时空间的实时演化,以证明出现相当大的横向纯自旋电流的Fe/Cu/Fe三层型的合成反铁磁体。我们进一步揭示了TSHE对电子结构细节的极端敏感性,这表明过渡金属合成反铁磁体中TSHE的大小和符号可以通过调整厚度或能带填充等参数来设计。除了是一个重要的一步,在我们的理解越来越复杂的skyrmionic系统的拓扑性质,我们的结果具有巨大的潜力,刺激发现反铁磁skyrmions。

英文摘要:

The topological Hall effect (THE), as one of the primary manifestations of non-trivial topology of chiral skyrmions, is traditionally used to detect the emergence of skyrmion lattices with locally ferromagnetic order. In this work we demonstrate that the appearance of non-trivial two-dimensional chiral textures with locally {\it anti}-ferromagnetic order can be detected through the spin version of the THE $-$ the topological spin Hall effect (TSHE). Utilizing the semiclassical formalism, here used to combine chiral antiferromagnetic textures with a density functional theory description of the collinear, degenerate electronic structure, we follow the real-space real-time evolution of electronic SU(2) wavepackets in an external electric field to demonstrate the emergence of sizeable transverse pure spin current in synthetic antiferromagnets of the Fe/Cu/Fe trilayer type. We further unravel the extreme sensitivity of the TSHE to the details of the electronic structure, suggesting that the magnitude and sign of the TSHE in transition-metal synthetic antiferromagnets can be engineered by tuning such parameters as the thickness or band filling. Besides being an important step in our understanding of the topological properties of ever more complex skyrmionic systems, our results bear great potential in stimulating the discovery of antiferromagnetic skyrmions.

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