Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 33: Transport - Nanoelectronics III: Molecular Electronics
TT 33.15: Vortrag
Dienstag, 8. März 2005, 17:45–18:00, TU H3027
Magnetic Field Dependent Band Structure in Multiwall Carbon Nanotubes — •Bernhard Stojetz1, Francois Triozon2, Stephan Roche2, Lazlo Forró3, and Christoph Strunk1 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg — 2Commissariat à l’Énergie Atomique, DRFMC/SPSMS, 38042 Grenoble, France — 3Institute of Physics of Complex Matter, FBS Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
We report conductance measurements for large diameter (30 - 40
nm)
individual multiwall carbon nanotubes in magnetic fields both
parallel
and perpendicular to the tube axis. A prestructured Al backgate
allows a substantial shift of the Fermi level.
The thin native oxide on the Al films provides a very efficient
electrostatic coupling between the gate and the tube.
The conductance of the nanotube was recorded as a function of
the
magnetic field B and
the gate voltage U. For parallel fields, both h/e- and
h/2e-periodic oscillations in the
magnetoconductance occur and lead to rhomb-shaped regions of low
conductance in the B-U-plane . In the perpendicular case, a
region of low conductance
forms at small gate voltges, which grows with increasing
magnetic
field.
The experimental observations are explained well by tight-
binding
bandstructure calculations for the outermost shell of a
multiwall nanotube in a magnetic field.