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

L. K. Dash, H. Ness, M. J. Verstraete, R. W. Godby

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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. (C) 2012 American Institute of Physics. []

Original languageEnglish
Article number064708
Pages (from-to)1-11
Number of pages11
JournalJournal of Chemical Physics
Issue number6
Publication statusPublished - 14 Feb 2012

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