title: Visualizing the Role of Molecular Orbitals in Charge Transport through Individual Diarylethene Isomers.
abstract: Diarylethene molecules are prototype molecular switches with their two isomeric forms exhibiting strikingly different conductance, while maintaining similar length. We employed low-temperature scanning tunneling microscopy (STM) to resolve the energy and the spatial extend of the molecular orbitals of the open and closed isomers when lying on a Au(111) surface. We find an intriguing difference in the extension of the respective HOMOs and a peculiar energy splitting of the formerly degenerate LUMO of the open isomer. We then lift the two isomers with the tip of the STM and measure the current through the individual molecules. By a simple analytical model of the transport, we show that the previously determined orbital characteristics are essential ingredients for the complete understanding of the transport properties. We also succeeded in switching the suspended molecules by the current, while switching the ones which are in direct contact to the surface occurs nonlocally with the help of the electric field of the tip.
authors: Institut für Experimentalphysik, Freie Universität Berlin , Arnimallee 14, Berlin 14195, Germany.
authors: Gaël
authors: G
authors: Reecht
authors: Institut für Experimentalphysik, Freie Universität Berlin , Arnimallee 14, Berlin 14195, Germany.
authors: Christian
authors: C
authors: Lotze
authors: Fachbereich Chemie, Universität Konstanz , Universitätsstraße 10, Konstanz 78457, Germany.
authors: Dmytro
authors: D
authors: Sysoiev
authors: Fachbereich Chemie, Universität Konstanz , Universitätsstraße 10, Konstanz 78457, Germany.
authors: Thomas
authors: T
authors: Huhn
authors: Institut für Experimentalphysik, Freie Universität Berlin , Arnimallee 14, Berlin 14195, Germany.
authors: Katharina J
authors: KJ
authors: Franke
keywords: charge transport; diarylethene; molecular switch; scanning tunneling microscopy; scanning tunneling spectroscopy