Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 22: Transport: Poster Session
TT 22.5: Poster
Mittwoch, 27. Februar 2008, 14:00–18:00, Poster B
Super-Poissonian current noise in coupled single-electron transistors — •Björn Kubala1,2, Göran Johansson3, and Jürgen König1 — 1TP III, Ruhr-Universität Bochum, Germany — 2Physics Department, ASC, and CeNS, Ludwig-Maximilians-Universität, 80333 Munich, Germany — 3MC2, Chalmers University Göteborg, Sweden
Non-Poissonian noise has been explored theoretically and experimentally in a variety of systems. We investigate zero-frequency noise and current-current crosscorrelations in networks of coupled single-electron transistors (SETs) within a real-time diagrammatic theory [1]. Calculating all noise contributions up to second order in the coupling strength, we include sequential and standard cotunneling processes, but also renormalization processes and cotunneling involving several transistor islands. For a single SET we find the familiar suppression of noise in double-barrier systems and reproduce results of orthodox and cotunneling theories.
A setup, where two SETs are capacitatively coupled, provides an inside into novel correlation effects, e.g., bunching of electrons as similarly found in semiconductor systems [2]. We identify a number of different mechanisms causing super-Poissonian noise, which could be experimentally investigated in coupled SETs.
[1] B. Kubala, G. Johansson, and J. König, Phys. Rev. B 73, 165316 (2006).
[2] A. Cottet, W. Belzig, and C. Bruder, Phys. Rev. B 70, 115315 (2004); S. S. Safonov et al., Phys. Rev. Lett. 91, 136801 (2003).