Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...

Posters Tuesday February 5
Poster 36:
Analysis of quantum transport features in complex carbon nanotube structures
Robert Frielinghaus
We have investigated two carbon nanotubes (CNTs) both in quantum transport
and in the transmission electron microscope by means of a novel sample
design. This enables us to determine the device structure unambiguously as
a two-fold single-walled CNT bundle and an individual triple-walled CNT,
respectively. The corresponding low-temperature transport experiments are,
to our knowledge, the first ones unambiguously conducted on these very
systems. The stability diagrams exhibit complex features as anti-crossings,
Fano-shaped coulomb peaks, and regular sawtooth patterns. The origin of
these features is only found with the detailed knowledge about the atomic
structure, which cannot be obtained with standard sample layouts. More precisely,
we measure capacitive and molecular interactions between the various
elements of the devices and the environment.
Poster 37:
Nanomechanical read-out of a single spin
Philipp Struck
The spin of a single electron in a suspended carbon nanotube can be read
out by using its coupling to the nano-mechanical motion of the nanotube. To
show this, we consider a single electron confined within a quantum dot formed
by the suspended carbon nanotube. The spin- orbit interaction induces a
coupling between the spin and one of the bending modes of the suspended
part of the nanotube. We calculate the response of the system to pulsed
external driving of the mechanical motion using a Jaynes-Cummings model.
To account for resonator damping, we solve a quantum master equation, with
parameters comparable to those used in recent experiments, and show how
information of the spin state of the system can be acquired by measuring
its mechanical motion. The latter can be detected by observing the current
through a nearby charge detector.[1]
[1] P. R. Struck, H. Wang, G. Burkard, arXiv:1212.1569
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