|Instituto de Ciencia de Materiales de Madrid|
|Condensed Matter Theory|
|Sigmund Kohler||home | cv | research | publications|
Dynamically broken symmetry in periodically gated quantum dots: Charge accumulation and dc-currentTomasz Kwapiński, Sigmund Kohler, and Peter Hänggi
Ukr. J. Phys. 55, 85 (2010)
Time-dependent electron transport through a quantum dot and double quantum dot systems in the presence of polychromatic external periodic quantum dot energy-level modulations is studied within the time evolution operator method for a tight-binding Hamiltonian. Analytical relations for the dc-current flowing through the system and the charge accumulated on a quantum dot are obtained for the zero-temperature limit. It is shown that in the presence of periodic perturbations the sideband peaks of the transmission are related to combination frequencies of the applied modulations. Moreover, for a small source-drain voltage the current is proportional to the derivative of the charge versus the position of a quantum dot energy level, while for the case of large chemical potentials the derivative of the current is proportional to the charge derivative. For a double quantum dot system under the influence of polychromatic perturbations the quantum pump effect is studied in the absence of source-drain and bias voltages. In the presence of spatial symmetry the charge is pumped through the system due to broken generalized parity symmetry.
[Condensed Matter Theory]
last modified: 18.6.2018 by Sigmund Kohler