Tracing Monopoles and Anti-monopoles in a Magnetic Hedgehog Lattice

TL;DR

This paper investigates the dynamics of magnetic monopoles and anti-monopoles in a lattice-based magnetic hedgehog lattice, revealing their movement, interactions, and relation to scalar spin chirality through simulations.

Contribution

It provides the first detailed simulation study of monopole and anti-monopole trajectories in a lattice system, highlighting effects of discretization on their motion.

Findings

Monopoles and anti-monopoles move and repel before annihilation.

Their motions are closely related to the scalar spin chirality.

Lattice discretization influences monopole dynamics.

Abstract

The magnetic hedgehog lattice (HL), which was recently discovered in the $B$20-type chiral magnet MnSi$_{1-x}$Ge$_x$, is a topological spin texture with a periodic array of magnetic monopoles and anti-monopoles. Within the continuum approximation, the monopoles and anti-monopoles are predicted to move, collide, and pair annihilate in an applied magnetic field, but it remains unclear how the lattice discretization affects their motions. Here, we study the trajectories of monopoles and anti-monopoles in a lattice system by simulated annealing with field sweep. We show that the monopoles and anti-monopoles move and repel before pair annihilations. We also clarify that their motions are closely related with the field dependence of the scalar spin chirality.