Vibronic States in Single Molecule Electron Transport

Abstract

A scanning tunneling microscope was used to study the electron transport through individual copper phthalocyanine molecules adsorbed on an ultrathin Al(2)O(3) film grown on a NiAl(110) surface. The differential conductance spectra display series of equally spaced features, which are attributed to vibronic states of individual molecules. The coupling of the electron current to the vibronic modes was observed to depend on the structures of the adsorbed molecules. Vibronic features were not observed for molecules adsorbed on the bare NiAl(110) surface due to spectral broadening.

Scanning Tunneling Spectroscopy of Individual PbSe Quantum Dots and Molecular Aggregates Stabilized in an Inert Nanocrystal Matrix

“…The combination of STM and STS has already proved very useful in probing the geometry and electronic structure of individual atoms and molecules and molecular aggregates at the atomic scale. [6][7][8][9][10][11][12] Furthermore, these techniques have been successfully used for the investigation of individual InAs, CdSe, and PbSe QDs, [13][14][15][16][17] as well as their twodimensional arrays. 18,19 In order to study a single, isolated QD or small aggregates of QDs with STM, they have to be immobilized on a conducting substrate.…”

Single-molecule transistors: Electron transfer in the solid state

“…Assuming that the electronic density of states of the tip is relatively featureless, this technique, known as scanning tunneling spectroscopy (STS), allows the measurement of the local density of states induced by the molecule. This novel spectroscopy has been revelatory, allowing the solid state observation of the alignment and broadening of occupied molecular orbitals [1], vibronic effects [2], inelastic electron tunneling via molecular vibrations [3] and spin flips [4], and electronic correlations such as Kondo physics [5].…”

Single-molecule transport in three-terminal devices

“…For instance, scanning tunneling microscopy (STM) has proven to be a powerful tool for investigating inelastic electron tunneling spectroscopy (IETS) on single molecules [6][7][8][9]. STM offers imaging capabilities which allows spectroscopic studies in a well-defined experimental geometry.…”