Liquid-crystal and Magnetic Skyrmions
By: Allison Teixeira
From: CFTC, Universidade de Lisboa, Portugal
At: Building C8, 8.2.39
[2023-02-23]
In recent decades, physical systems with topological protection have been a focus of extensive research. The so-called skyrmions are an example of topologically stable structures in both liquid crystals and magnetic systems. In liquid crystals, skyrmions can emerge due to the competition between the different director deformations in the system and with the surface anchoring. Once formed, liquid-crystal skyrmions behave as particles, responding to an oscillating applied electric field by moving and interacting with each other. In this work, we propose a simple model to describe the dynamic of the skyrmion as an active particle and compare the results with experimental data. We reproduced the motion of the skyrmion and showed the dependence of its direction and velocity on the frequency of the electric field. On the other hand, the so-called Dzyaloshinskii–Moriya interaction is the principal responsible for the emergence of skyrmions in magnetic systems. In this respect, when its dynamic is beyond the particle-like description, the magnetic skyrmion can deform due to a self-induced field while moving. As a consequence, its effective mass changes. Performing a Monte Carlo simulation, we characterized the skyrmion deformation during its steady movement and calculated its effective mass as a function of its velocity. Besides, we found that when the skyrmion moves faster, the large self-induced deformation triggers topological transitions.
