Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...
Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...
Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...
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Posters Tuesday February 5<br />
Poster 34:<br />
Spin-orbit effects in electronic transport in DNA-CNT hybrids<br />
Sergio Ulloa<br />
We report on theoretical studies of electronic transport in the archetypical<br />
molecular hybrid formed by DNA wrapped around single-walled carbon<br />
nanotubes (CNTs). Using a Green’s function formalism in a π-orbital tightbinding<br />
representation, we investigate the role that spin-orbit interactions<br />
play on the CNT in the case of the helicoidal electric field induced by the<br />
polar nature of the adsorbed DNA molecule. We find that spin polarization<br />
of the current can take place in the absence of magnetic fields, depending<br />
strongly on the direction of the wrapping and length of the helicoidal field.<br />
These findings open new routes for using CNTs in spintronic devices.<br />
Poster 35:<br />
Covalent functionalization of carbon nanotubes with tetramanganese complexes<br />
Robert Frielinghaus<br />
We present first results on the covalent chemical functionalization of carbon<br />
nanotubes (CNTs) with polynuclear Mn 4 coordination complexes. Raman<br />
spectra give direct and indirect evidence of a successful reaction. It can only<br />
be achieved for tubes which contain defects with carboxylic groups. Changes<br />
in the magnetization behavior of the Mn 4 complexes due to the bonding<br />
to the CNTs are analyzed using data obtained in temperature-dependent<br />
SQUID measurements.<br />
These results are correlated with bright- and dark field high-resolution transmission<br />
electron microscopy measurements that show the repartition of the<br />
Mn 4 decoration on the CNTs. Its elemental analysis capabilities, energydispersive<br />
x-ray spectroscopy and electron energy loss spectroscopy, proof the<br />
existence of Mn on the CNTs. Investigating several oxidation strengths we<br />
can show that already a mild oxidation that leaves the nanotubes intact in<br />
terms of a finite electrical conductance is sufficient for functionalization. This<br />
is important for the future application of this material in transport devices.<br />
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