Non-equilibrium current and relaxation dynamics of a charge-fluctuating quantum dot
Institut für Theoretische Physik A and JARA-Fundamentals of Future Information Technology, RWTH Aachen University - D-52056 Aachen, Germany, EU
2 Physikalisches Institut, Universität Bonn - D-53115 Bonn, Germany, EU
Corresponding author: email@example.com
Accepted: 22 April 2010
We study the steady-state current in a minimal model for a quantum dot dominated by charge fluctuations and analytically describe the time evolution into this state. The current is driven by a finite-bias voltage V across the dot, and two different renormalization group methods are used to treat small-to-intermediate local Coulomb interactions. The corresponding flow equations can be solved analytically, which allows to identify all microscopic cutoff scales. Exploring the entire parameter space we find rich non-equilibrium physics which cannot be understood by simply considering the bias voltage as an infrared cutoff. For the experimentally relevant case of left-right asymmetric couplings, the current generically shows a power law suppression for large V. The relaxation dynamics towards the steady state features characteristic oscillations as well as an interplay of exponential and power law decay.
PACS: 05.60.Gg – Quantum transport / 71.10.-w – Theories and models of many-electron systems / 73.63.Kv – Electronic transport in nanoscale materials and structures: Quantum dots
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