Propagation dynamics of spin excitations along skyrmion strings
Propagation dynamics of spin excitations along skyrmion strings
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DOI：
10.1038/s41467-019-14095-0
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发表时间：
2020-01-14
影响因子：
16.6
通讯作者：
Tokura, Y.
中科院分区：
文献类型：
--
作者：
Seki, S.;Garst, M.;Tokura, Y.
磁性斯格明子是一种拓扑孤子，具有二维旋转自旋纹理，最近作为稳定的粒子状物体而引起了人们的关注。在三维系统中，斯格明子可以在三维中延伸，形成坚固且灵活的弦结构，其独特的拓扑和对称性预计将承载重要的功能响应。在这里，我们通过实验证明了手性晶格磁体 Cu2OSeO3 的自旋激发沿斯格明子弦的相干传播。我们发现这种传播在方向上是不可逆的，并且不可逆的程度以及群速度和衰减长度在很大程度上取决于激发模式的特征。这些自旋激发可以传播超过 50 μm 的距离，证明了斯格明子弦结构优异的长程有序性质。我们结合实验和理论分析提供了对斯格明子弦激励的传播动力学的全面解释，并提出了沿着这种拓扑保护的弦单向信息传输的可能性。斯格明子在三维空间中的传播动力学引起了越来越多的关注。在这里，作者证明了手性晶格磁体 Cu2OSeO3 的自旋激发沿斯格明子弦在超过 50 μm 的距离上的相干和非互易传播。
Magnetic skyrmions, topological solitons characterized by a two-dimensional swirling spin texture, have recently attracted attention as stable particle-like objects. In a three-dimensional system, a skyrmion can extend in the third dimension forming a robust and flexible string structure, whose unique topology and symmetry are anticipated to host nontrivial functional responses. Here we experimentally demonstrate the coherent propagation of spin excitations along skyrmion strings for the chiral-lattice magnet Cu2OSeO3. We find that this propagation is directionally non-reciprocal and the degree of non-reciprocity, as well as group velocity and decay length, are strongly dependent on the character of the excitation modes. These spin excitations can propagate over a distance exceeding 50 mu m, demonstrating the excellent long-range ordered nature of the skyrmion-string structure. Our combined experimental and theoretical analyses offer a comprehensive account of the propagation dynamics of skyrmion-string excitations and suggest the possibility of unidirectional information transfer along such topologically protected strings. The propagation dynamics of skyrmions in three dimensions have attracted increasing attention. Here, the authors demonstrate the coherent and non-reciprocal propagation of spin excitations along skyrmion strings for the chiral-lattice magnet Cu2OSeO3 over a distance exceeding 50 mu m.