Real-Space Plasmon Imaging Reveals Modified Electronic Structure of Gold at the Monolayer Limit

Andrei Bylinkin; Philippe Roelli; Naveen Shetty; Rositsa Yakimova; Ulrich Starke; Camilla Coletti; Stiven Forti; Alexei Zakharov; Vyacheslav M. Silkin; Samuel Lara-Avila; Rainer Hillenbrand

arXiv · 2603.05030

Real-Space Plasmon Imaging Reveals Modified Electronic Structure of Gold at the Monolayer Limit

Andrei Bylinkin·Philippe Roelli·Naveen Shetty·Rositsa Yakimova·Ulrich Starke·Camilla Coletti·Stiven Forti·Alexei Zakharov·Vyacheslav M. Silkin·Samuel Lara-Avila·Rainer Hillenbrand

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Abstract

Atomically thin materials exhibit electronic and optical properties distinct from their three-dimensional counterparts. For metals, particularly gold, monolayer studies remain largely unexplored due to fabrication and characterisation challenges. Here we report the first optical study of a stable quasi-freestanding gold monolayer formed by Au intercalation between graphene and SiC. Mid-infrared nanoimaging reveals plasmon-polaritons with wavelengths nearly an order of magnitude shorter than free-space light. Analysis of their dispersion using a Drude model yields a relaxation time of $\tau = 18\,$fs, comparable to bulk gold, and a Drude weight of $D = 1.3\,$mS$\cdot$eV, nearly twice the bulk expectation. These results establish monolayer gold as a two-dimensional metal, opening opportunities for nanoscale photonics, plasmonics and ultra-thin electronics.

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Andrei Bylinkin, Philippe Roelli, Naveen Shetty, Rositsa Yakimova, Ulrich Starke, Camilla Coletti, Stiven Forti, Alexei Zakharov, Vyacheslav M. Silkin, Samuel Lara-Avila, Rainer Hillenbrand. 2026-03-05. Real-Space Plasmon Imaging Reveals Modified Electronic Structure of Gold at the Monolayer Limit. https://arxiv.org/abs/2603.05030

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