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

TY - JOUR

T1 - Functionality in single-molecule devices

T2 - Model calculations and applications of the inelastic electron tunneling signal in molecular junctions

AU - Dash, L. K.

AU - Ness, H.

AU - Verstraete, M. J.

AU - Godby, R. W.

PY - 2012/2/14

Y1 - 2012/2/14

N2 - 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. [http://dx.doi.org/10.1063/1.3684627]

AB - 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. [http://dx.doi.org/10.1063/1.3684627]

UR - http://www.scopus.com/inward/record.url?scp=84857327502&partnerID=8YFLogxK

U2 - 10.1063/1.3684627

DO - 10.1063/1.3684627

M3 - Article

VL - 136

SP - 1

EP - 11

JO - The Journal of Chemical Physics

JF - The Journal of Chemical Physics

SN - 0021-9606

IS - 6

M1 - 064708

ER -