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Electron transport in carbon nanotube-metal systems: contact effects
R. Gutiérrez , N. Ranjan, S. Krompiewski, and G. Cuniberti
Deutsche Physikalische Gesellschaft, AKF Frühjahrstagung 2004 German Physical Society, Spring Meeting 2004 (Symposium Organic and Hybrid Systems for Future Electronics)
2004.03.08-12; Regensburg, Germany
| Carbon nanotubes (CNT) posses a very large application
potential in the rapid developing field of molecular
electronics. Infinite single-wall metallic CNTs have
theoretically a conductance of 2G0, (G0 = \frac2e2h)
because of the two electronic bands crossing the Fermi
level. For finite size CNTs experiments have shown that
other values are also possible, indicating a very
strong influence of the contacts. We study electron
transport in single- and double-wall CNTs contacted to
metallic electrodes with a fcc(111) surface within the
Landauer transport formalism combined with Green
function techniques. The electronic structure of the
CNTs is described with a simple p-orbital model.We show
that the symmetry of the contact region may lead in
some cases to blocking of one of the transport channels
reducing the conductance to 1G0 for single-wall CNTs.
In the case of double-wall systems with both inner and
outer shells being metallic, non-diagonal selfenergy
contributions from the electrodes may induce mixing of
the CNT's channels, again reducing the conductance from
the theoretically expected value (4G0). Finally, we
discuss the influence of inter-wall interactions on the
conductance.
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Prof. Dr. Gianaurelio Cuniberti
secretariat:
postal address:
Institute for Materials Science
TU Dresden
01062 Dresden, Germany
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