Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France.
Los Alamos National Laboratory, Los Alamos, NM, USA.
Science. 2022 Mar 4;375(6584):1025-1030. doi: 10.1126/science.abe4441. Epub 2022 Mar 3.
The motion of a spin excitation across topologically nontrivial magnetic order exhibits a deflection that is analogous to the effect of the Lorentz force on an electrically charged particle in an orbital magnetic field. We used polarized inelastic neutron scattering to investigate the propagation of magnons (i.e., bosonic collective spin excitations) in a lattice of skyrmion tubes in manganese silicide. For wave vectors perpendicular to the skyrmion tubes, the magnon spectra are consistent with the formation of finely spaced emergent Landau levels that are characteristic of the fictitious magnetic field used to account for the nontrivial topological winding of the skyrmion lattice. This provides evidence of a topological magnon band structure in reciprocal space, which is borne out of the nontrivial real-space topology of a magnetic order.
自旋激发穿过拓扑非平庸磁有序的运动表现出一种偏转，类似于轨道磁场中带电粒子所受洛伦兹力的效应。我们使用极化非弹性中子散射来研究锰硅化物中螺旋管晶格中磁振子（即玻色集体自旋激发）的传播。对于垂直于螺旋管的波矢，磁振子谱与精细间隔的出现朗道能级一致，这些能级是为了说明螺旋子晶格的非平庸拓扑缠绕而使用的虚构磁场的特征。这为倒易空间中拓扑磁振子能带结构提供了证据，这种结构源于磁有序的非平凡实空间拓扑。
