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arXiv · 2110.00882

Higgs and Goldstone spin-wave modes in striped magnetic texture

Matías Grassi·Moritz Geilen·Kosseila Ait Oukaci·Yves Henry·Daniel Lacour·Daniel Stoeffer·Michel Hehn·Philipp Pirro·Matthieu Bailleul
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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.

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Matías Grassi, Moritz Geilen, Kosseila Ait Oukaci, Yves Henry, Daniel Lacour, Daniel Stoeffer, Michel Hehn, Philipp Pirro, Matthieu Bailleul. 2021-10-02. Higgs and Goldstone spin-wave modes in striped magnetic texture. https://doi.org/10.1103/physrevb.105.094444

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