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O: Fachverband Oberflächenphysik

O 37: Posters: Plasmonics, Electronic Structure and Spin-Orbit Interaction, Semiconductor and Insulator Surfaces, Nanostructures

O 37.98: Poster

Dienstag, 1. April 2014, 18:30–22:00, P2

Oligothiophene nanorings as electron resonators for whispering gallery modes — •Gaël Reecht¹, Hervé Bulou¹, Fabrice Scheurer¹, Virginie Speisser¹, Fabrice Mathevet², and Guillaume Schull¹ — ¹IPCMS , Strasbourg, France — ²Laboratoire de Chimie des Polymères, Paris, France

Recently, conjugated molecular wires were investigated using scanning tunneling microscopy (STM) [1]. These studies showed that the electronic structure of these oligomers can be approximated by a (nearly) free electron gas confined to a 1D box. Using a recent "on-surface" synthesis method [2], we obtained oligothiophene nanowires and nanocycles on a Au(111) surface. The electronic properties of these structures were energetically and spatially resolved using scanning tunneling spectroscopy (STS).This study reveals large differences between the electronic properties of the linear and cyclic structures. These differences find their origin in the close-ended nature of the cyclothiophene resonances which must be treated with periodic boundary conditions. A more detailed analysis shows that cyclothiophene must be considered as a ribbon (i.e., having an effective width) rather than a purely 1D structure. A fascinating consequence is that the molecular nanorings act as whispering gallery mode resonators for electrons, opening the way for new applications in quantum electronics [3].

[1]. Wang, S and al. Phys. Rev. Lett., 106, 206803 (2011)

[2]. Grill, L and al., Nature Nano, 2, 687 (2007)

[3]. Reecht, G and al. Phys. Rev. Lett., 110, 056802 (2013)