384 research outputs found
Helicoidal Fields and Spin Polarized Currents in CNT-DNA Hybrids
We report on theoretical studies of electronic transport in the archetypical
molecular hybrid formed by DNA wrapped around single-walled carbon nanotubes
(CNTs). Using a Green's function formalism in a -orbital tight-binding
representation, we investigate the role that spin-orbit interactions play on
the CNT in the case of the helicoidal electric field induced by the polar
nature of the adsorbed DNA molecule. We find that spin polarization of the
current can take place in the absence of magnetic fields, depending strongly on
the direction of the wrapping and length of the helicoidal field. These
findings open new routes for using CNTs in spintronic devices.Comment: 4 pages, 5 figure
A computationally efficient method for calculating the maximum conductance of disordered networks: Application to 1-dimensional conductors
Random networks of carbon nanotubes and metallic nanowires have shown to be
very useful in the production of transparent, conducting films. The electronic
transport on the film depends considerably on the network properties, and on
the inter-wire coupling. Here we present a simple, computationally efficient
method for the calculation of conductance on random nanostructured networks.
The method is implemented on metallic nanowire networks, which are described
within a single-orbital tight binding Hamiltonian, and the conductance is
calculated with the Kubo formula. We show how the network conductance depends
on the average number of connections per wire, and on the number of wires
connected to the electrodes. We also show the effect of the inter-/intra-wire
hopping ratio on the conductance through the network. Furthermore, we argue
that this type of calculation is easily extendable to account for the upper
conductivity of realistic films spanned by tunneling networks. When compared to
experimental measurements, this quantity provides a clear indication of how
much room is available for improving the film conductivity.Comment: 7 pages, 5 figure
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