Electron−Phonon Interactions in Single Octanedithiol Molecular Junctions

We study the charge transport properties and electron-phonon interactions in single molecule junctions, each consisting of an octanedithiol molecule covalently bound to two electrodes. Conductance measurements over a wide temperature range establish tunneling as the dominant charge transport process. Inelastic electron tunneling spectroscopy performed on individual molecular junctions provides a chemical signature of the molecule and allows electron-phonon interaction induced changes in the conductance to be explored. By fitting the conductance changes in the molecular junction using a simple model for inelastic transport, it is possible to estimate the phonon damping rates in the molecule. Finally, changes in the inelastic spectra are examined in relation to conductance switching events in the junction to demonstrate how changes in the configuration of the molecule or contact geometry can affect the conductance of the molecular junction.