Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 20: Transport: Nanoelectronics I - Quantum Dots, Wires, Point Contacts 1

TT 20.3: Vortrag

Dienstag, 26. Februar 2008, 14:45–15:00, EB 202

Adiabatic pumping in a quantum dot-Aharonov-Bohm interferometer — •Bastian Hiltscher, Michele Governale, and Jürgen König — Institut für Theoretische Physik III, Ruhr-Universität Bochum, 44780 Bochum, Germany

We study adiabatic pumping in Aharonov-Bohm interferometers, where a quantum dot is embedded in one or in both arms. Charge pumping occurs if two parameters are changed periodically in time. The limit of small frequencies defines the adiabatic regime.
For our calculations we use a real-time diagrammatic technique and combine the properties of AB interferometers [1] with the properties of adiabatic pumping [2] for dots with strong Coulomb interaction. By performing a perturbation expansion in the pumping frequency and in the tunnel-coupling strength we calculate the magnetic-flux dependence of the pumped charge and compare it with the results for rectification of an AC voltage, which may yield an effective DC current as well.
We get information about the character of adiabatic pumping, which could be interpreted as peristaltic, but phase-coherent. Furthermore we find, that adiabatic pumping and rectification show different symmetries and, thereby, are distinguishable.

[1]J. König and Y. Gefen, Phys. Rev. B 65, 045316 (2002).

[2]J. Splettstoesser, M. Governale, J. König, and R. Fazio, Phys. Rev. B 74, 085305 (2006).