Inertia and chiral edge modes of a skyrmion magnetic bubble

TL;DR

This paper investigates the dynamics of skyrmion magnetic bubbles, revealing they possess inertia and exhibit edge wave modes, which deviate from the simple charged particle analogy and enhance understanding of their physical behavior.

Contribution

The study derives the inertia (mass) of skyrmion bubbles from ferromagnet theory and identifies edge wave modes, providing a more complete dynamical model.

Findings

Skyrmion bubbles have finite inertia.

Edge wave modes travel with different speeds in opposite directions.

Deviations from the charged particle model are explained by inertia and edge waves.

Abstract

The dynamics of a vortex in a thin-film ferromagnet resembles the motion of a charged massless particle in a uniform magnetic field. Similar dynamics is expected for other magnetic textures with a nonzero skyrmion number. However, recent numerical simulations revealed that skyrmion magnetic bubbles show significant deviations from this model. We show that a skyrmion bubble possesses inertia and derive its mass from the standard theory of a thin-film ferromagnet. Besides center-of-mass motion, other low energy modes are waves on the edge of the bubble traveling with different speeds in opposite directions.