A Hall viscosity for skyrmion via magnon interaction

TL;DR

This paper derives a Hall viscosity term in skyrmion dynamics caused by Dzyaloshinskii-Moriya interaction, revealing its dependence on skyrmion properties and magnon interactions, with implications for asymmetric Hall angles.

Contribution

It introduces a novel Hall viscosity term in skyrmion motion directly linked to DMI, expanding understanding of skyrmion Hall effects in insulating magnets.

Findings

Hall viscosity is proportional to skyrmion charge.

Skyrmion Hall angle depends on shape, size, and exchange-DMI ratio.

Hall angles are similar for skyrmions with opposite charges.

Abstract

We identify a Hall viscosity term directly from the Dzyaloshinskii-Moriya interaction (DMI), that breaks parity symmetry, in the skyrmion motion of insulating magnets by time-averaging the magnon contribution to all orders. The viscosity term is proportional to the skyrmion charge. Skyrmion Hall angle shows significant dependence on the skyrmion shape and size, the ratio of exchange over DMI parameters, while roughly independent of the Gilbert damping parameter. The Hall angles have the same magnitude for opposite skyrmion charges. We speculate a velocity-dependent Hall viscosity contribution to seek asymmetric Hall angles for the opposite charges.