Dipolar-drift and collective instabilities of skyrmions in crossed nonuniform electric and magnetic fields in a chiral magnetic insulator

TL;DR

This paper investigates the complex dynamics and instabilities of skyrmions in multiferroic insulators under crossed nonuniform electric and magnetic fields, revealing new drift behaviors and hydrodynamical instabilities.

Contribution

It introduces a novel analysis of skyrmion motion and instabilities in multiferroic materials with crossed field gradients, highlighting new drift effects and hydrodynamical phenomena.

Findings

Skyrmions exhibit spiral motion under magnetic field gradients.

Electric fields induce a magneto-dipolar Hall effect in skyrmion drift.

Identified three regimes of hydrodynamical instability caused by skyrmion drift.

Abstract

Skyrmions dynamics in the approximation of point-particle skyrmions is considered in the multiferroic insulators, where the spiral magnetic structure is accompanied by finite electric dipole moment. The skyrmion motion is studied in the gradients of perpendicular magnetic and electric fields. The nonuniform magnetic field with a fixed gradient magnitude leads to the spiral motion, where skyrmion circulates in the plane perpendicular to the direction of magnetic field. The frequency of circulation is fixed by the derivative of the external magnetic field and the magnitude of the dipole moment. Application of additional electric field which perpendicular to the magnetic field, but their gradients have same direction leads to the drift motion of skyrmions resulting in the magneto-dipolar Hall effect. Hydrodynamics of the gas of interacting skyrmions in crossed nonuniform electric and magnetic fields shows the new type of hydrodynamical instability caused by the drift motion. Three regimes of instability are described.