Low temperature measurements on structured graphene
(with F. Molitor, J. Güttinger, D. Graf, T. Ihn and K. Ensslin)
Graphene is a promising material to investigate
mesoscopic phenomena in two-dimensions (2d). Unique
electronic properties, such as massless carriers, strong electron-hole
symmetry near the charge neutrality point, and
weak spin-orbit coupling makes graphene interesting
for high mobility electronics, for tracing quantum
electrodynamics in 2d solids, and for the realization of
spin-qubits, which might be a promising building block for solid-state qunatum computation.
We investigate nanostructured graphene devices in terms of low temperature transport experiments.
Among quantum hall measurements on a side gated graphene hall bar, where the half integer hall effect has been
reproduced, we currently investigate graphene single electron transistors.
For example, we report on Coulomb
blockade and Coulomb diamond measurements on an
etched graphene quantum dot tunable by graphene side
gates.
FIGURE - Scanning force micrograph (SFM) of an etched graphene singel electron transistor with minimum feature size of approx. 50nm; Coulomb diamond measurements on this device; corresponding Coulomb peaks and SFM image of the final device. Image are adapted from Ref. [2].
[1] Local gating of a graphene Hall
bar by graphene side gates;
F. Molitor, J. Güttinger, C. Stampfer, D. Graf, T. Ihn, and K. Ensslin, arXiv:0709.2970v1, (2007).
[2] Tunable Coulomb blockade in
nanostructured graphene;
C. Stampfer, J. Güttinger, F. Molitor, D. Graf, T. Ihn, and K. Ensslin, arXiv:0709.3799, (2007).
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