SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 76: Plasmonics and Nanooptics III: Light-Matter Interaction and Spectroscopy II
O 76.2: Vortrag
Donnerstag, 30. März 2023, 10:45–11:00, WIL A317
Atomically resolved optical spectroscopy and microscopy in a scanning-tunneling microscope: Theory and experiment — •Tomas Neuman1,2, Anna Roslawska1, Benjamin Doppagne1, Andrei G. Borissov2, Michelangelo Romeo1, Fabrice Scheurer1, Javier Aizpurua3, and Guillaume Schull1 — 1Universite de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000, Strasbourg, France — 2Institut des sciences Moleculaires d'Orsey (ISMO), UMR 8214, CNRS, Universite Paris-Saclay, 91405 Orsay Cedex, France — 3Center for Materials Physics and DIPC, Paseo Manuel de Lardizabal 5, Donostia-San Sebastian 20018, Spain
We present a joint theoretical and experimental study of the optical properties of individual small organic molecules excited electrically by the plasmonic tip of a STM. We investigate how these properties vary as a function of the tip position with atomic-scale resolution. We show that the variation of the spectral position and width of the electroluminescence emission line of the molecular exciton can be linked with the DC Stark effect (induced by the static voltage across the tip-substrate gap) and the plasmonic Purcell effect due to the plasmonic response of the tip, respectively. We interpret the spectral line shift map as an image of the difference between the excited- and ground-state electron densities of the molecule, and the tip-position-dependent map of the excitonic line-width variation as an image of the transition electron density. In contrast, the map of light intensity emitted by the molecule reveals the information about the electronic mechanism leading to the tip-mediated generation of the exciton.