Particle model for skyrmions in metallic chiral magnets: Dynamics, pinning, and creep

By Shizeng Lin, Charles Reichhardt, C. Batista, Avadh Saxena. 2013

255 citations recorded by the source corpus.

Recently spin textures called skyrmions have been discovered in certain chiral magnetic materials without spatial inversion symmetry, and have attracted enormous attention due to their promising application in spintronics since only a low applied current is necessary to drive their motion. When a conduction electron moves around the skyrmion, its spin is fully polarized by the spin texture and acquires a quantized phase; thus, the skyrmion yields an emergent electrodynamics that in turn determines skyrmion motion and gives rise to a finite Hall angle. While Skyrmions behave as particles, no particle level description of their dynamics exists to date. Such a model would have tremendous impact on understanding skyrmion dynamics by theoretical analysis and computational modeling. Here we derive the equation of motion from a microscopic continuum model and obtain the short-range interaction between skyrmions, and the interaction between skyrmions and defects. Skyrmions also experience a Magnus force perpendicular to their velocity due to the underlying emergent electromagnetic field. We validate the equation of motion by studying the depinning transition using both the particle and the continuum models. By using the particle description, we explain the recent experimental observations of the rotation of a skyrmion lattice in the presence of a temperature gradient. We also predict quantum and thermal creep motion of skyrmions in the pinning potential.

Subfields: Atomic and Molecular Physics, and Optics, Biomedical Engineering, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/8cdf50f01d5eff6299d496f465777f7691057ec3

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In Atomic and Molecular Physics, and Optics

In Biomedical Engineering

In Condensed Matter Physics

Citations in the corpus

Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems (2018, methodology): “The influence of disorder and thermal fluctuations on the driven motion of single skyrmions have been investigated either using particle-simulations (Lin et al., 2013) or by micromagnetic modeling (Sampaio et al.”
Skyrmions in magnetic multilayers (2017, background): “The motion occurs at a very low current density (on the order of 10(2) A/cm(2)), indicative of negligible pinning effects from material imperfection in single crystalline samples [68].”
Ginzburg-Landau theory for skyrmions in inversion-symmetric magnets with competing interactions (2015, background): “[50] Shi-Zeng Lin, Charles Reichhardt, Cristian D.”
Skyrmion-electronics: writing, deleting, reading and processing magnetic skyrmions toward spintronic applications (2019, background): “topological Magnus force [108, 155, 275], which is always perpendicular to the velocity.”