Coherent sliding dynamics and spin motive force driven by crossed magnetic fields in a chiral helimagnet

Abstract

We demonstrate that the chiral soliton lattice formed from a chiral helimagnet exhibits a coherent sliding motion when a time-dependent magnetic field is applied parallel to the helical axis, in addition to a static field perpendicular to the helical axis. To describe the coherent sliding, we use the collective coordinate method and a numerical analysis. We also show that the time-dependent sliding velocity causes a time-varying Berry cap which creates a spin motive force. A salient feature of the chiral soliton lattice is the appearance of a strongly amplified spin motive force which is directly proportional to the macroscopic number of solitons (magnetic kinks).