Pöllath S, Wild J, Heinen L, Meier T N G, Kronseder M, Tutsch L, Bauer A, Berger H, Pfleiderer C, Zweck J, Rosch A, Back C H
Institut für Experimentelle Physik, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany.
Institut für Theoretische Physik, Universität zu Köln, D-50937 Köln, Germany.
Phys Rev Lett. 2017 May 19;118(20):207205. doi: 10.1103/PhysRevLett.118.207205.
The chiral magnet Cu_{2}OSeO_{3} hosts a Skyrmion lattice that may be equivalently described as a superposition of plane waves or a lattice of particlelike topological objects. A thermal gradient may break up the Skyrmion lattice and induce rotating domains, raising the question of which of these scenarios better describes the violent dynamics at the domain boundaries. Here, we show that in an inhomogeneous temperature gradient caused by illumination in a Lorentz transmission electron microscope different parts of the Skyrmion lattice can be set into motion with different angular velocities. Tracking the time dependence, we show that the constant rearrangement of domain walls is governed by dynamic 5-7 defects arranging into lines. An analysis of the associated defect density is described by Frank's equation and agrees well with classical 2D Monte Carlo simulations. Fluctuations of boundaries show a surgelike rearrangement of Skyrmion clusters driven by defect rearrangement consistent with simulations treating Skyrmions as point particles. Our findings underline the particle character of the Skyrmion.
手性磁体Cu₂OSeO₃中存在一种斯格明子晶格，它可以等效地描述为平面波的叠加或类粒子拓扑物体的晶格。热梯度可能会破坏斯格明子晶格并诱导旋转畴，这就引发了一个问题：这些情况中哪一种能更好地描述畴边界处的剧烈动力学。在此，我们表明，在洛伦兹透射电子显微镜中由光照引起的非均匀温度梯度下，斯格明子晶格的不同部分可以以不同的角速度运动。通过跟踪时间依赖性，我们表明畴壁的持续重排由排列成线的动态5-7缺陷控制。相关缺陷密度的分析由弗兰克方程描述，并且与经典的二维蒙特卡罗模拟结果吻合良好。边界的波动显示出由缺陷重排驱动的斯格明子簇的类似涌动的重排，这与将斯格明子视为点粒子的模拟结果一致。我们的发现强调了斯格明子的粒子特性。
