# Collective spin dynamics of Z2 vortex crystals in triangular Kitaev-Heisenberg antiferromagnets

## TL;DR

This paper identifies distinctive dynamical spin response signatures, including pseudo-Goldstone modes and multi-scattered intensity profiles, as key indicators of Z2 vortex crystals in layered triangular Kitaev-Heisenberg antiferromagnets.

## Contribution

It reveals how to experimentally detect Z2 vortex crystals through their unique dynamical spin response signatures.

## Key findings

- Presence of low-frequency pseudo-Goldstone phonon modes
- Multi-scattered intensity profile at higher frequencies
- Signatures of large vortex sizes and solitonic spin profiles

## Abstract

We show that the mesoscopic incommensurate $\mathbb{Z}_2$ vortex crystals proposed for layered triangular anisotropic magnets can be most saliently identified by two distinctive signatures in dynamical spin response experiments: The presence of pseudo-Goldstone `phonon' modes at low frequencies $\omega$, associated with the collective vibrations of the vortex cores, and a characteristic multi-scattered intensity profile at higher $\omega$, arising from a large number of Bragg reflections and magnon bandgaps. These are direct fingerprints of the large vortex sizes and magnetic unit cells and the solitonic spin profile around the vortex cores.