Experimental observation of one-dimensional motion of skyrmion in chiral magnet

The interplay between dimensionality and topology manifests in magnetism via both exotic texture morphology and novel dynamics. A free magnetic skyrmion exhibits the skyrmion Hall effect under electric currents. Once it is confined in one-dimensional (1D) channels, the skyrmion Hall effect would be suppressed, and the current-driven skyrmion speed should be boosted by the non-adiabatic spin transfer torque β. Here, we experimentally demonstrate the 1D skyrmion motion without the skyrmion Hall effect. Using FeGe as a benchmark, two brand-new approaches have been taken: one is to use the stripes of a spatially modulated spin helix as natural 1D channels to restrict skyrmion, the other is to confine an 80-nm-size skyrmion in a 100-nm-wide nanostripe. In-situ electrical Lorentz microscopy is employed to investigate the current-driven motion of skyrmions under the nanosecond current pulses. Surprisingly, the slope of the current-velocity curve for 1D skyrmion motion is enhanced almost by an order of magnitude comparable to that in 2D case, owing to a large β/α in FeGe. The large magnitude of β/α is well reproduced by theoretical modeling and first-principles calculations after revisiting the Zhang-Li's model. Utilizing the 1D skyrmion dynamics would thus be a highly promising route to implement topological spintronic devices.