Higgs and Goldstone spin-wave modes in striped magnetic texture

TL;DR

This paper reports the direct observation of Goldstone and Higgs spin-wave modes in a periodically modulated ferromagnetic film, providing a practical platform to study symmetry breaking dynamics at room temperature.

Contribution

It demonstrates the experimental detection of Goldstone and Higgs modes in a magnetic system with periodic modulation, a significant step forward in understanding symmetry breaking.

Findings

Direct observation of Goldstone and Higgs modes at room temperature

Use of microwave and optical techniques for detection

Provides a platform for exploring symmetry breaking dynamics

Abstract

Spontaneous symmetry breaking is ubiquitous in physics. Its spectroscopic signature consists in the softening of a specific mode upon approaching the transition from the high symmetry side and its subsequent splitting into a zero-frequency "Goldstone" mode and a non-zero-frequency "Higgs" mode. Although they determine the whole system dynamics, these features are difficult to address in practice because of their vanishing coupling to most experimental probes and/or their strong interaction with other fluctuations. In this work, we consider a periodic magnetic modulation occurring in a ferromagnetic film with perpendicular-to-plane magnetic anisotropy and directly observe its Goldstone and Higgs spin-wave modes at room temperature using microwave and optical techniques. This simple system constitutes a particularly convenient platform for further exploring the dynamics of symmetry breaking.