Regensburg 2004 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 11: Nanoelektronik I: Quantenpunkte, -dr
ähte, -punktkontakte
TT 11.1: Vortrag
Dienstag, 9. März 2004, 09:30–09:45, H19
Single-electron effects and quantum fluctuations in metallic multi-island geometries — •Björn Kubala1,2, Göran Johansson2, and Jürgen König1 — 1Institut für Theoretische Physik III, Ruhr-Universität Bochum, D-44780 Bochum — 2Institut für Theoretische Festkörperphysik, Universität Karlsruhe, D-76128 Karlsruhe
We have developed a method to model electron transport through a complex network of single-electron transistors.
Based on a real-time transport theory [1], we automatically generate all diagrams up to second order in tunnel coupling and calculate their contributions to the current. This captures quantum fluctuations and multi-channel Kondo physics for each island as well as the mutual influence of tunneling effects on two neighbouring islands. The latter is essential for a detailed analysis of recent experiments [2], where an SET, capacitively coupled to a single electron box, was used as a sensitive electrometer, measuring the charge state of the box. Here the backaction between measurement device (SET) and system (box) is fully included in our approach.
We will discuss the applicability of our method to different experimental setups of metallic islands, coupled capacitively and/or by tunneling barriers, and possible generalizations to the case of magnetic or superconducting leads.
[1] H. Schoeller and G. Schön, Phys. Rev. B 50, 18 436 (1994); J. König, H. Schoeller, and G. Schön, Phys. Rev. Lett. 78, 4482 (1997)
[2] R. Schäfer et al., cond-mat/0205223; K. W. Lehnert et al., Phys. Rev. Lett. 91, 106801 (2003).