Self-induced Floquet magnons in magnetic vortices

TL;DR

This paper demonstrates a novel self-induced Floquet magnon state in magnetic vortices, where nonlinear interactions lead to Floquet band formation without external periodic driving, opening new pathways for controlling magnon dynamics.

Contribution

It introduces a self-induced Floquet state in magnetic vortices resulting from nonlinear interactions, a significant advancement in Floquet engineering of magnon band structures.

Findings

Floquet bands emerge from vortex core oscillations.

Nonlinear interactions induce core gyration and band renormalization.

Self-induced Floquet states enable new control of magnon dynamics.

Abstract

Driving condensed matter systems with periodic electromagnetic fields can result in exotic states not found in equilibrium. Termed Floquet engineering, such periodic driving applied to electronic systems can tailor quantum effects to induce topological band structures and control spin interactions. However, Floquet engineering of magnon band structures in magnetic systems has proven challenging so far. Here, we present a class of Floquet states in a magnetic vortex that arise from nonlinear interactions between the vortex core and microwave magnons. Floquet bands emerge through the periodic oscillation of the core, which can be initiated by either driving the core directly or pumping azimuthal magnon modes. For the latter, the azimuthal modes induce core gyration through nonlinear interactions, which in turn renormalizes the magnon band structure. This represents a self-induced mechanism for Floquet band engineering and offers new avenues to study and control nonlinear magnon dynamics.