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Functionality in single-molecule devices: Model calculations and applications of the inelastic electron tunneling signal in molecular junctions

TitleFunctionality in single-molecule devices: Model calculations and applications of the inelastic electron tunneling signal in molecular junctions
Publication TypeJournal Article
Year of Publication2012
AuthorsDash, L. K., Ness H., Verstraete M. J., & Godby R. W.
Keywordsab initio calculations; electric fields; Green's function methods; Molecular electronics; tunnelling
Abstract

We analyze how functionality could be obtained within single-molecule devices by using a combination of non-equilibrium Green's functions and ab initio calculations to study the inelastic transport properties of single-molecule junctions. First, we apply a full non-equilibrium Green's function technique to a model system with electron-vibration coupling. We show that the features in the inelastic electron tunneling spectra (IETS) of the molecular junctions are virtually independent of the nature of the molecule-lead contacts. Since the contacts are not easily reproducible from one device to another, this is a very useful property. The IETS signal is much more robust versus modifications at the contacts and hence can be used to build functional nanodevices. Second, we consider a realistic model of a organic conjugated molecule. We use ab initio calculations to study how the vibronic properties of the molecule can be controlled by an external electric field which acts as a gate voltage. The control, through the gate voltage, of the vibron frequencies and (more importantly) of the electron-vibron coupling enables the construction of functionality: nonlinear amplification and/or switching is obtained from the IETS signal within a single-molecule device.

JournalThe Journal of Chemical Physics
Volume136
Issue6
Pagination064708
URLhttp://dx.doi.org/10.1063/1.3684627
Date Published2012/03
Citation Key1291