TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.15.2.065
TI  - Skyrmion jellyfish in driven chiral magnets
PY  - 2023/08/17
UR  - https://scipost.org/SciPostPhys.15.2.065
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 15
IS  - 2
SP  - 065
A1  - del Ser, Nina
AU  - Lohani, Vivek
AB  - Chiral magnets can host topological particles known as skyrmions which carry an exactly quantised topological charge $Q=-1$. In the presence of an oscillating magnetic field $B_1(t)$, a single skyrmion embedded in a ferromagnetic background will start to move with constant velocity v$_{trans}$. The mechanism behind this motion is similar to the one used by a jellyfish when it swims through water. We show that the skyrmion's motion is a universal phenomenon, arising in any magnetic system with translational modes. By projecting the equation of motion onto the skyrmion's translational modes and going to quadratic order in $B_1(t)$, we obtain an analytical expression for v$_{trans}$ as a function of the system's linear response. The linear response and consequently v$_{trans}$ are influenced by the skyrmion's internal modes and scattering states, as well as by the ferromagnetic background's Kittel mode. The direction and speed of v$_{trans}$ can be controlled by changing the polarisation, frequency and phase of the driving field $B_1(t)$. For systems with small Gilbert damping parameter $\alpha$, we identify two distinct physical mechanisms used by the skyrmion to move. At low driving frequencies, the skyrmion's motion is driven by friction, and $v_{trans}\sim\alpha$, whereas at higher frequencies above the ferromagnetic gap the skyrmion moves by magnon emission, and $v_{trans}$ becomes independent of $\alpha$.
ER  -

@Article{10.21468/SciPostPhys.15.2.065,
	title={{Skyrmion jellyfish in driven chiral magnets}},
	author={Nina del Ser and Vivek Lohani},
	journal={SciPost Phys.},
	volume={15},
	pages={065},
	year={2023},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.15.2.065},
	url={https://scipost.org/10.21468/SciPostPhys.15.2.065},
}