Emergent electrodynamics of skyrmions in a chiral magnet
Emergent electrodynamics of skyrmions in a chiral magnet
复制标题
DOI：
10.1038/nphys2231
复制
发表时间：
2012-04-01
期刊：
影响因子：
19.6
通讯作者：
Rosch, A.
中科院分区：
文献类型：
--
作者：
Schulz, T.;Ritz, R.;Rosch, A.
当电子在平滑变化的非共线磁性结构中移动时，其自旋方向不断适应，从而感应作用在磁性结构和电子上的力。这些力可以通过新兴电动力学的电场和磁场来描述(1-4)。所谓的斯格明子（最近在手性磁体 (5-7) 中发现的一种磁旋动）的拓扑量子化缠绕数已被预测为每个斯格明子恰好感应出一个量子的涌现磁通量。因此，移动的斯格明子预计会遵循法拉第感应定律感应出一个新兴电场，该定律继承了这种拓扑量子化(8)。在这里，我们报告霍尔效应测量，定量地建立预测的出现的电动力学。我们获得了斯格明子从杂质中脱钉（电流密度仅为 10(6) A m(-2)）及其随后运动的定量证据。极小的电流密度和简单的输运测量相结合，为手性磁体中斯格明子的新兴电动力学和真实电动力学之间的联系提供了基本见解，从长远来看，这可能对应用很重要。
When an electron moves in a smoothly varying non-collinear magnetic structure, its spin orientation adapts constantly, thereby inducing forces that act both on the magnetic structure and on the electron. These forces may be described by electric and magnetic fields of an emergent electrodynamics(1-4). The topologically quantized winding number of so-called skyrmions-a type of magnetic whirl discovered recently in chiral magnets(5-7)-has been predicted to induce exactly one quantum of emergent magnetic flux per skyrmion. A moving skyrmion is therefore expected to induce an emergent electric field following Faraday's law of induction, which inherits this topological quantization(8). Here we report Hall-effect measurements that establish quantitatively the predicted emergent electrodynamics. We obtain quantitative evidence for the depinning of skyrmions from impurities (at current densities of only 10(6) A m(-2)) and their subsequent motion. The combination of exceptionally small current densities and simple transport measurements offers fundamental insights into the connection between the emergent and real electrodynamics of skyrmions in chiral magnets, and might, in the long term, be important for applications.