Finite-bias electronic transport of molecules in a water solution
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2010Access:
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I. Rungger, X. Chen, U. Schwingenschlögl, and S. Sanvito, Finite-bias electronic transport of molecules in a water solution, Physical Review B, 81, 2010, 235407Download Item:
Finite-bias.pdf (Published (publisher's copy) - Peer Reviewed) 2.832Mb
Abstract:
The effects of water wetting conditions on the transport properties of molecular nanojunctions are investigated
theoretically by using a combination of empirical-potential molecular-dynamics and first-principles
electronic-transport calculations. These are at the level of the nonequilibrium Green?s-function method implemented
for self-interaction corrected density-functional theory. We find that water effectively produces electrostatic
gating to the molecular junction with a gating potential determined by the time-averaged water dipole
field. Such a field is large for the polar benzene-dithiol molecule, resulting in a transmission spectrum shifted
by about 0.6 eV with respect to that of the dry junction. The situation is drastically different for carbon
nanotubes CNTs . In fact, because of their hydrophobic nature the gating is almost negligible so that the
average transmission spectrum of wet Au/CNT/Au junctions is essentially the same as that in dry conditions.
This suggests that CNTs can be used as molecular interconnects also in water-wet situations, for instance, as
tips for scanning tunnel microscopy in solution or in biological sensors.
Sponsor
Grant Number
Science Foundation Ireland (SFI)
331952
Author's Homepage:
http://people.tcd.ie/sanvitosDescription:
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Series/Report no:
Physical Review B81
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Full text availableKeywords:
Physics, molecular nanojunctionsSubject (TCD):
Nanoscience & MaterialsLicences: