Real-space observation of skyrmion clusters with mutually orthogonal skyrmion tubes
Real-space observation of skyrmion clusters with mutually orthogonal skyrmion tubes
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DOI：
10.1103/physrevb.100.104401
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发表时间：
2019-06
影响因子：
3.7
通讯作者：
Hayley R. O. Sohn;S. Vlasov;V. M. Uzdin;A. Leonov;I. Smalyukh
中科院分区：
文献类型：
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作者：
Hayley R. O. Sohn;S. Vlasov;V. M. Uzdin;A. Leonov;I. Smalyukh
我们报告了在手性液晶和铁磁体中发现并直接可视化了具有相互正交取向的组成孤立skyrmion的skyrmion团簇。我们发现，新生的锥形状态下吸引skyrmion间的潜力，而一个包容的均匀状态导致排斥skyrmion-skyrmion相互作用。在改变层厚度和/或表面锚定时，可以识别不同Skyrmion相互作用机制之间的交叉。我们发展了一个描述两种类型的skyrmions和它们相互作用的基本机制的唯象理论。我们发现，孤立的水平skyrmion具有相同的极性可以接近垂直孤立skyrmion从两侧，从而构成两个能量不同的配置，也观察到实验。在相互吸引的极端状态下，Skyrmions相互缠绕，形成具有起伏的紧凑超级结构。我们还指出，我们的数值模拟skyrmion集团是有效的，在相应的参数范围内的A相区的立方helimagnets。
We report the discovery and direct visualization of skyrmion clusters with mutually-orthogonal orientations of constituent isolated skyrmions in chiral liquid crystals and ferromagnets. We show that the nascent conical state underlies attracting inter-skyrmion potential, whereas an encompassing homogeneous state leads to the repulsive skyrmion-skyrmion interaction. The crossover between different regimes of skyrmion interaction could be identified upon changing layer thickness and/or the surface anchoring. We develop a phenomenological theory describing two types of skyrmions and the underlying mechanisms of their interaction. We show that isolated horizontal skyrmions with the same polarity may approach a vertical isolated skyrmion from both sides and thus constitute two energetically-different configurations which are also observed experimentally. In an extreme regime of mutual attraction, the skyrmions wind around each other forming compact superstructures with undulations. We also indicate that our numerical simulations on skyrmion clusters are valid in a parameter range corresponding to the A-phase region of cubic helimagnets.