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Electron transport in carbon nanotube-metal systems: contact effects
N. Ranjan, R. Gutiérrez, S. Krompiewski and G. Cuniberti
Nanostructured systems: Basic Properties and Technology
2004.05.31-02(06); Bedlewo, Poland
| Carbon nanotubes (CNT) posses a very large application
potential in molecular electronic devices. Infinite
single-wall metallic CNTs have theoretically a
conductance of 2G0
(G0=2e2/h) 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 contact. We study electron transport
in single- and double-wall CNTs contacted to metallic
electrodes with an fcc(111) surface within the Landauer
transport formalism combined with Green function
techniques. The electronic structure of the CNTs is
described with a simple -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 self energy
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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last modified: 2020.12.01 Tue
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Prof. Dr. Gianaurelio Cuniberti
secretariat:
postal address:
Institute for Materials Science
TU Dresden
01062 Dresden, Germany
visitors and courier address:
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