Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 38: Poster Session Transport
TT 38.10: Poster
Mittwoch, 16. März 2011, 14:00–18:00, P3
Shot-noise of tunnel current coupled to a local plasmon — •Fei Xu, Federica Haupt, and Wolfgang Belzig — Fachbereich Physik, Universität Konstanz, D- 78457 Konstanz, Germany
Current noise in mesoscopic conductors is an
important tool to investigate quantum many-body effects in electron
transport. If the noise is measured at frequencies in the quantum
range, ℏ ω≫ kBT, the measurement amounts to the detection
of photons produced by current fluctuations. This is important in
view of recent experiments on photon-emission from
tunnel junctions formed by a scanning tunneling microscope on a
metallic surface [1,2]. These works showed a considerable
intensity of photons emitted with a frequency larger than the applied
bias voltage ℏ ω>eV [1,2].
While photons with frequency ℏ ω <eV can be readily
interpreted in terms of fluctuations in single-electron transfer
processes, over-bias (ℏω> eV) photon emission is a fingerprint
of electronic correlations. We address the problem of over-bias photon emission
formulating it in terms of current fluctuations in a
conductor interacting with an electromagnetic environment. The latter
can mediate cooperative processes in which two electrons team up
crossing the junction, emitting a single phonon with energy up to
2eV [3]. To describe the set-up of Ref. [1], we
employ a minimal model consisting of a local tunnel junction coupled
to an electric RLC circuit, whose dynamics mimics the local plasmon
mode in the metal junction.
G. Schull, et al. PRL 102, 057401 (2009).
N. L. Schneider, et al. PRL 105, 026601 (2010).
J. Tobiska, et al., PRL. 96, 096801 (2006).