Real-Space Plasmon Imaging Reveals Modified Electronic Structure of Gold at the Monolayer Limit
Year: 2026
Type: preprint
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 $τ= 18\,$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.
Source: arXiv (Cornell University)
Institutions: CIC nanoGUNE, Chalmers University of Technology, Linköping University, Max Planck Institute for Solid State Research, Italian Institute of Technology, National Enterprise for NanoScience and NanoTechnology, Center for Nanotechnology Innovation, Lund University, MAX IV Laboratory, University of the Basque Country
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1575104644, G1622782223, G2262748287, G3480869486, G3681454997, G4042783231, G425668148, G434337789, G451917667, Quantum criticality and new quantum matter in two-dimensional Dirac materials, G513388344, G5310398836, 2D material-based technology for industrial applications (2D-TECH), G5635509179, G5683704876, G5967599077, G6033112984, G6512509876, G7084143925, Probing the limits of Mid-IR frequency upconversion with a hybrid tip-antenna nanoresonator
OpenAlex ID: W7134044591