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O: Fachverband Oberflächenphysik

O 43: Scanning probe microscopy: light matter interaction at atomic scales – Poster

O 43.15: Poster

Dienstag, 10. März 2026, 14:00–16:00, P2

Influence of Polarons on Tunneling and Optical Spectra of Molecules Adsorbed on Dielectric Layers — •Jan Friese — Institute of Physics, Czech Academy of Sciences, Cukrovarnicka 10, Prague, 16200, Czech Republic

Light-assisted scanning tunneling microscopy has enabled the simultaneous probing of transport and optical properties of individual molecules with atomic-scale precision. This technique relies on electronically decoupling the molecules from the metallic substrate by depositing them on dielectric spacer layers. However, these spacers are often formed by ionic crystals, such as NaCl. The phononic response of these ionic layers can significantly impact the observed experimental features due to polaronic effects. Their understanding requires a bottom-up theoretical description accounting for the dynamics of the dielectric layer triggered by electronic transitions in the molecule.

Here we address this challenge and use the polaron-formalism to model the interaction of phonons in the dielectric layer with changes of the charge density in the molecule due to optical or charge transfer excitations. With that, two-time correlation functions and consequently spectral functions can be derived to account for the dynamics involved in substrate reorganization processes following a change of charge density in an adsorbed molecule. The results can be used to calculate features like the reorganization energy, and positions, widths and shapes of peaks in tunneling and optical spectra.

Keywords: Polaron; Molecule; Surface; Dielectric Layer; Optical Properties