1201.5254 (L. K. Dash et al.)

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

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

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: non-linear amplification and/or switching is obtained from the
IETS signal within a single-molecule device.

View original: http://arxiv.org/abs/1201.5254