Nonlinear dynamics of skyrmion strings

Fuente: arXiv
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Main Author: Kravchuk, Volodymyr P.
Format: Preprint
Published: 2023
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author Kravchuk, Volodymyr P.
author_facet Kravchuk, Volodymyr P.
contents The skyrmion core, percolating the volume of the magnet, forms a skyrmion string -- the topological Dirac-string-like object. Here we analyze the nonlinear dynamics of skyrmion string in a low-energy regime by means of the collective variables approach which we generalized for the case of strings. Using the perturbative method of multiple scales (both in space and time), we show that the weakly nonlinear dynamics of the translational mode propagating along the string is captured by the nonlinear Schroedinger equation of the focusing type. As a result, the basic "planar-wave" solution, which has a form of a helix-shaped wave, experiences modulational instability. The latter leads to the formation of cnoidal waves. Both types of cnoidal waves, dn- and cn-waves, as well as the separatrix soliton solution, are confirmed by the micromagnetic simulations. Beyond the class of the traveling-wave solutions, we found Ma-breather propagating along the string. Finally, we proposed a generalized approach, which enables one to describe nonlinear dynamics of the modes of different symmetries, e.g. radially symmetrical or elliptical.
format Preprint
id arxiv_https___arxiv_org_abs_2306_11866
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Nonlinear dynamics of skyrmion strings
Kravchuk, Volodymyr P.
Pattern Formation and Solitons
Strongly Correlated Electrons
The skyrmion core, percolating the volume of the magnet, forms a skyrmion string -- the topological Dirac-string-like object. Here we analyze the nonlinear dynamics of skyrmion string in a low-energy regime by means of the collective variables approach which we generalized for the case of strings. Using the perturbative method of multiple scales (both in space and time), we show that the weakly nonlinear dynamics of the translational mode propagating along the string is captured by the nonlinear Schroedinger equation of the focusing type. As a result, the basic "planar-wave" solution, which has a form of a helix-shaped wave, experiences modulational instability. The latter leads to the formation of cnoidal waves. Both types of cnoidal waves, dn- and cn-waves, as well as the separatrix soliton solution, are confirmed by the micromagnetic simulations. Beyond the class of the traveling-wave solutions, we found Ma-breather propagating along the string. Finally, we proposed a generalized approach, which enables one to describe nonlinear dynamics of the modes of different symmetries, e.g. radially symmetrical or elliptical.
title Nonlinear dynamics of skyrmion strings
topic Pattern Formation and Solitons
Strongly Correlated Electrons
url https://arxiv.org/abs/2306.11866