title: AFM Imaging of Mercaptobenzoic Acid on Au(110): Submolecular Contrast with Metal Tips.
abstract: A self-assembled monolayer of mercaptobenzoic acid (MBA) on Au(110) is investigated with scanning tunneling and atomic force microscopy (STM and AFM) and density functional calculations. High-resolution AFM images obtained with metallic tips show clear contrasts between oxygen atoms and phenyl moieties. The contrast above the oxygen atoms is due to attractive covalent interactions, which is different than previously reported high-resolution images, where Pauli repulsion dominated the image contrast. We show that the bonding of MBA to the substrate occurs mainly through dispersion interactions, whereas the thiol-Au bond contributes only a quarter of the adsorption energy. No indication of Au adatoms mediating the thiol-Au interaction was found in contrast to other thiol-bonded systems. However, MBA lifts the Au(110)-(2 × 1) reconstruction.
authors.affiliation: Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel , 24098 Kiel, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Hauptmann
authors.affiliation: Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
authors.forename: Roberto
authors.initials: R
authors.lastname: Robles
authors.affiliation: Instituto de Física de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Universidad Nacional de Rosario, Avenida Pellegrini 250, 2000 Rosario, Argentina.
authors.forename: Paula
authors.initials: P
authors.lastname: Abufager
authors.affiliation: Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), Paseo Manuel de Lardizabal 5 and Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Lorente
authors.affiliation: Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel , 24098 Kiel, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Berndt