2004/04/23 by R. Guyon, T. Jonckheere, Guyon, R. +11
Engineering · Physics and Astronomy · #FOS: Physical sciences #Force Microscopy Techniques and Applications #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Molecular Junctions and Nanostructures #Surface and Thin Film Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.48550/arxiv.cond-mat/0404571
13 pages, 8 figures
arxiv created 2004/04/23 · openalex publication_date 2004/04/23 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The transport properties of a simple model for a finite level structure (a molecule or a dot) connected to metal electrodes in an alternating current scanning tunneling microscope (AC-STM) configuration is studied. The finite level structure is assumed to have strong binding properties with the metallic substrate, and the bias between the STM tip and the hybrid metal-molecule interface has both an AC and a DC component. The finite frequency current response and the zero frequency photo-assisted shot noise are computed using the Keldysh technique, and examples for a single site molecule (a quantum dot) and for a two-site molecule are examined. The model may be useful for the interpretation of recent experiments using an AC-STM for the study of both conducting and insulating surfaces, where the third harmonic component of the current is measured. The zero frequency photo-assisted shot noise serves as a useful diagnosis for analyzing the energy level structure of the molecule. The present work motivates the need for further analysis of current fluctuations in electronic molecular transport.