Inertia and Chiral Edge Modes of a Skyrmion Magnetic Bubble

TLDR

The dynamics of a vortex in a thin‑film ferromagnet resembles that of a charged massless particle in a uniform magnetic field, and similar behavior is anticipated for other magnetic textures with a nonzero skyrmion number. The study demonstrates that a skyrmion bubble has inertia and derives its mass using standard thin‑film ferromagnet theory. The authors derive the bubble’s mass from the standard theory of a thin‑film ferromagnet, establishing its inertial dynamics. Numerical simulations reveal that skyrmion magnetic bubbles deviate from the expected vortex dynamics and exhibit additional low‑energy edge modes propagating at different speeds in opposite directions.

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.