Stavros Komineas (University of Crete) Dynamics of skyrmions and of topologically trivial solitons
Skyrmionic textures are found as minimum energy solutions in magnetic materials where the chiral Dzyaloshinskii-Moriya interaction is present. They are characterized by an integer-valued topological invariant called the skyrmion number Q in this context. The model supports (i) an axially symmetric skyrmion with Q=1, (ii) an axially symmetric texture with Q=0 that is called the skyrmionium, (iii) bimeron configurations that are understood as transformations of the Q=1 skyrmion , and (iv) a chiral droplet that is a topologically trivial, Q=0, skyrmion-antiskyrmion configuration [2,3].
We will introduce the Landau-Lifshitz equation for the statics and dynamics of the magnetization in ferromagnets. We will present a fundamental relation that links topology and magnetization dynamics . A straightforward result is that topological textures (nonzero Q) are spontaneously pinned and follow Hall dynamics, while topologically trivial textures (Q=0) are accelerated by forces and follow Newtonian dynamics [4,5]. The laws are examplified by simulating the dynamics of the above-mentioned four skyrmionic textures [3,5].
It is gradually understood that skyrmionic textures are realizations of fractons, a type of unusual particle of restricted mobility discussed within spin lattice models and higher-rank gauge theories .
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