Dr. Stefan Kirchner, Max-Planck-Institute for the
Physics of Complex Systems, Dresden
"Non-linear transport in nanoscale devices: Superperturbation theory approach
to thermoelectric transport in strongly correlated quantum dots"
- 14.02.2012 14:00 Uhr
- N-270 in PGI (Peter Grünberg Institut 04.8)
The description of transport in correlated matter beyond the linear response
regime is usually based on the semiclassical Boltzmann equation in the
relaxation time approximation. Such an approach relies on the existence of
well-defined quasiparticles which is not always warranted.
Perturbative methods on the other hand are straightforwardly extended onto the
Schwinger-Keldysh contour but often suffer from internal inconsistencies like
non-conservation of the charge current away from particle-hole symmetry.
We devise a novel superperturbation theory on the Schwinger-Keldysh contour to
treat transport through a quantum dot.
The reference system is the interacting particle-hole symmetric Anderson
model, which has been extensively studied by Yamada and Yosida and others for
the equilibrium case, and by Oguri and others when out of equilibrium.
Our method is free of such issues as the
non-conservation of the current and allows for the study of various transport
properties away from particle-hole symmetry. Perturbative in nature,
this approach is generalizable to more complex situations.
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