Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 30: Phenomena at Semiconductor Surfaces
O 30.5: Vortrag
Dienstag, 26. Februar 2008, 13:00–13:15, MA 041
Bistability of single cyclooctadiene molecules on Si(001) induced by inelastic electron tunneling — •Christophe Nacci, Jérôme Lagoute, Xi Liu, and Stefan Fölsch — Paul Drude Institute for Solid-State Electronics, Hausvogteiplatz 5-7, 10117 Berlin, Germany
The tip-induced switching of single 1,5 cyclooctadiene molecules (COD) on Si(001) was studied by low-temperature scanning tunneling microscopy.
COD (C8H12) is a cyclic alkene with a twisted boat double-degenerate configuration which adsorbs in two different structures: the so-called bridge structure and the upright structure, with the bridge structure being the prevalent conformation [1]. Time spectroscopy of the tunnel current with the tip positioned over the molecule adsorbed in the bridge structure reveals fluctuations between two levels of current reminiscent to statistical telegraph noise. This behavior is interpreted as a reversible dynamic switching of the adsorbed molecule between two degenerate conformations triggered by inelastic single-electron excitation. First measurements on COD adsorbed in the upright structure reveal a significantly different noise response with an enhanced quantum yield and a lifted degeneracy of the current level population probabilities.
J. H. Cho et al. Phys. Rev. B 64, 241306 (2001)