Berlin 2005 – scientific programme
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TT: Tiefe Temperaturen
TT 37: Transport - Fluctuations and Noise
TT 37.4: Talk
Wednesday, March 9, 2005, 11:00–11:15, TU H3027
Tunneling through coupled quantum dots - Dephasing and Counting Statistics — •Gerold Kießlich1, Peter Samuelsson2, Andreas Wacker2, and Eckehard Schöll1 — 1Institut für Theoretische Physik, TU Berlin, Hardenbergstr. 36, 10623 Berlin — 2Dept. of Physics, University of Lund, Box 118, SE-22100 Lund, Sweden
The electronic transport through two coupled quantum dots (QDs) in series can be described either in a fully coherent approach (e.g. density matrix description) or in a simple sequential tunneling treatment (Pauli master equation with Fermi’s Golden rule for coupling between the QDs). It turns out that both descriptions provide the same average current for noninteracting QDs [1]. In contrast, the zero-frequency spectral power density is different for intermediate coupling strengths between the QDs reflecting its sensitivity on coherence in the tunneling process. In a phenomenological escape model we study the influence of the transition between the sequential and coherent limit on the current fluctuations. In particular, the counting statistics is obtained by means of a stochastic path-integral method [2]. The noise and the skewness are discussed in detail with respect to decoherence in the tunneling process.
[1] H. Sprekeler, G. Kießlich, A. Wacker, and E. Schöll. Phys. Rev. B, 125328, (2004)
[2] S. Pilgram, A.N. Jordan, A.V. Sukhorukov, and M. Büttiker. Phys. Rev. Lett. 90, 206801 (2003)