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arXiv · 2601.10493

Plasmon dynamics in graphene

Suheng Xu·Birui Yang·Nishchhal Verma·Rocco A. Vitalone·Brian Vermilyea·Miguel Sánchez Sánchez·Julian Ingham·Ran Jing·Yinming Shao·Tobias Stauber·Angel Rubio·Milan Delor·Mengkun Liu·Michael M. Fogler·Cory R. Dean·Andrew Millis·Raquel Queiroz·D. N. Basov
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Abstract

Plasmon are collective oscillations of mobile electrons with dynamics controlled by their charge stiffness("Drude weight"). Using terahertz spacetime metrology, we probe Plasmon dynamics of mono- and bi-layer graphene. In both systems, the experimentally measured Drude weight systematically exceeds the prediction based on non-interacting electronic system. The relative enhancement increases as the carrier density decreases. We attribute the observed deviation to the interplay of interactions and wave function structure of the Dirac fermions in multi-layer graphene. Our results establish that pseudospin structure of the single-particle electronic wave function can directly influence collective excitations, with implications that extend beyond graphene to a broad class of quantum materials.

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Suheng Xu, Birui Yang, Nishchhal Verma, Rocco A. Vitalone, Brian Vermilyea, Miguel Sánchez Sánchez, Julian Ingham, Ran Jing, Yinming Shao, Tobias Stauber, Angel Rubio, Milan Delor, Mengkun Liu, Michael M. Fogler, Cory R. Dean, Andrew Millis, Raquel Queiroz, D. N. Basov. 2026-01-15. Plasmon dynamics in graphene. https://arxiv.org/abs/2601.10493

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