Spin Inertia as a Source of Topological Magnons: Chiral Edge States from Coupled Precession and Nutation

TL;DR

This paper explores how spin inertia-induced nutational excitations can hybridize with precessional magnons to produce topological edge states in magnetic materials, opening new avenues for topological phase engineering.

Contribution

It demonstrates that hybridization between precessional and nutational magnons, enabled by angular-momentum-breaking interactions, can induce topological phenomena in spin-wave spectra.

Findings

Topological gaps open between precessional and nutational bands.

Chiral edge states appear in honeycomb ferromagnets due to hybridization.

Spin inertia can be used to engineer topological phases in magnetic materials.

Abstract

Spin inertia has been demonstrated to give rise to high-frequency nutational excitations beyond the conventional low-frequency precessional modes. Here, we demonstrate that the hybridization between precessional and nutational magnons may give rise to topological phenomena in the spin-wave spectrum. This hybridization requires the presence of interactions breaking angular-momentum conservation, such as the pseudodipolar interaction. We show on the example of a honeycomb ferromagnet how topological gaps open between the precessional and nutational bands that host chiral edge states in slab geometries. Our work establishes a theoretical foundation for exploring inertial spin dynamics as a new route to engineer topological phases in magnetic materials.