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arXiv · 2107.11578

Collective magnetic excitations in AA- and AB-stacked graphene bilayers

M. Sánchez Sánchez·G. Gómez-Santos·T. Stauber
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Abstract

We discuss novel transverse plasmon-polaritons that are hosted by AA- and AB-stacked bilayer graphene due to perfect nesting. They are composed of oscillating counterflow currents in between the layers, giving a clear interpretation for these collective modes as magnetic excitations carrying magnetic moment parallel to the planes. For AA-stacked bilayer graphene, these modes can reach zero frequency at the neutrality point and we thus predict a symmetry broken ground-state leading to in-plane orbital ferromagnetism. Even though it could be hard to detect them in real solid-state devices, these novel magnetic plasmons should be observable in artificial set-ups such as optical lattices. Also, our results might be relevant for magic angle twisted bilayer graphene samples as their electronic properties are mostly determined by confined AA-stacked regions.

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M. Sánchez Sánchez, G. Gómez-Santos, T. Stauber. 2021-12-11. Collective magnetic excitations in AA- and AB-stacked graphene bilayers. https://doi.org/10.1103/physrevb.104.245412

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