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

Posters Monday February 4
Poster 12:
An alternative functional renormalization group approach to the single impurity
Anderson model
Michael Kinza
We present an alternative functional renormalization group (fRG) approach
to the single-impurity Anderson model at finite temperatures. Starting
with the exact self-energy and interaction vertex of a small system (’core’)
containing a correlated site, we switch on the hybridization with a noninteracting
bath in the fRG-flow and calculate spectra of the correlated site.
Different truncations of the RG-flow-equations and choices of the core are
compared and discussed. Furthermore we calculate the linear conductance
and the magnetic susceptibility as functions of temperature and interaction
strength. The signatures of Kondo physics arising in the flow are compared
with numerical renormalization group results.
Poster 13:
Conductance scaling in Kondo correlated quantum dots: role of level asymmetry
Lukas Merker
The low temperature electrical conductance through correlated quantum dots
provides a sensitive probe of the physics (e.g., of Fermi-liquid vs non-Fermiliquid
behavior) of such systems. Here, we investigate the role of level asymmetry
(gate voltage) and local Coulomb repulsion (charging energy) on the
low temperature and low field scaling properties of the linear conductance of a
quantum dot described by the single level Anderson impurity model. We use
the numerical renormalization group and renormalized perturbation theory
to quantify the regime of gate voltages and charging energies where universal
Kondo scaling may be observed and also quantify the deviations from this
universal behavior with increasing gate voltage away from the Kondo regime
and with decreasing charging energy. Our results could be a useful guide for
detailed experiments on conductance scaling in semiconductor and molecular
quantum dots exhibiting the Kondo effect.
Coauthors
T. A. Costi, E. Munoz, S. Kirchner
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