title: Contacting a conjugated molecule with a surface dangling bond dimer on a hydrogenated Ge(001) surface allows imaging of the hidden ground electronic state.
abstract: Fabrication of single-molecule logic devices requires controlled manipulation of molecular states with atomic-scale precision. Tuning molecule-substrate coupling is achieved here by the reversible attachment of a prototypical planar conjugated organic molecule to dangling bonds on the surface of a hydrogenated semiconductor. We show that the ground electronic state resonance of a Y-shaped polyaromatic molecule physisorbed on a defect-free area of a fully hydrogenated surface cannot be observed by scanning tunneling microscopy (STM) measurements because it is decoupled from the Ge bulk states by the hydrogen-passivated surface. The state can be accessed by STM only if the molecule is contacted with the substrate by a dangling bond dimer. The reversibility of the attachment processes will be advantageous in the construction of surface atomic-scale circuits composed of single-molecule devices interconnected by the surface dangling bond wires.
authors.affiliation: Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University , Reymonta 4, PL 30-059, Krakow, Poland.
authors.forename: Szymon
authors.initials: S
authors.lastname: Godlewski
authors.forename: Marek
authors.initials: M
authors.lastname: Kolmer
authors.forename: Hiroyo
authors.initials: H
authors.lastname: Kawai
authors.forename: Bartosz
authors.initials: B
authors.lastname: Such
authors.forename: Rafal
authors.initials: R
authors.lastname: Zuzak
authors.forename: Mark
authors.initials: M
authors.lastname: Saeys
authors.forename: Paula
authors.initials: P
authors.lastname: de Mendoza
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Echavarren
authors.forename: Christian
authors.initials: C
authors.lastname: Joachim
authors.forename: Marek
authors.initials: M
authors.lastname: Szymonski