Topological transport of deconfined hedgehogs in magnets

TL;DR

This paper develops a hydrodynamic theory for magnetic hedgehogs in magnets, revealing their topological transport properties and proposing a nonlocal measurement method for their detection, with implications for spintronics.

Contribution

It introduces a topological conservation law for hedgehog textures and connects their dynamics to measurable nonlocal signals in magnetic materials.

Findings

Hedgehog textures obey a topological conservation law.

Nonlocal transport signals decay inversely with distance.

Potential for long-range signal propagation in magnetic systems.

Abstract

We theoretically investigate the dynamics of magnetic hedgehogs, which are three-dimensional topological spin textures that exist in common magnets, focusing on their transport properties and connections to spintronics. We show that fictitious magnetic monopoles carried by hedgehog textures obey a topological conservation law, based on which a hydrodynamic theory is developed. We propose a nonlocal transport measurement in the disordered phase, where the conservation of the hedgehog flow results in a nonlocal signal decaying inversely proportional to the distance. The bulk-edge correspondence between hedgehog number and skyrmion number, the fictitious electric charges arising from magnetic dynamics, and the analogy between bound states of hedgehogs in ordered phase and the quark confinement in quantum chromodynamics are also discussed. Our study points to a practical potential in utilizing hedgehog flows for long-range neutral signal propagation or manipulation of skyrmion textures in three-dimensional magnetic materials.