Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 22: Transport - Nanoelectronics II: Quantum Dots and Wires, Point Contacts

TT 22.5: Vortrag

Montag, 7. März 2005, 15:00–15:15, TU H2053

Transport properties of single channel quantum wires with an impurity: Influence of finite length and temperature on average current and noise — •Fabrizio Dolcini¹, Björn Trauzettel², Inès Safi³, and Hermann Grabert¹ — ¹Albert-Ludwigs-Universität, Freiburg — ²Leiden University, The Netherlands — ³Université Paris-Sud, France

The inhomogeneous Tomonaga Luttinger liquid model describing an interacting quantum wire adiabatically coupled to non-interacting leads is analyzed in the presence of a weak impurity within the wire. Due to strong electronic correlations in the wire, the effects of impurity backscattering, finite bias, finite temperature, and finite length lead to characteristic non-monotonic parameter dependencies of the average current [1]. We discuss oscillations of the non-linear current voltage characteristics that arise due to reflections of plasmon modes at the impurity and quasi Andreev reflections at the contacts. The finite frequency current noise is also investigated in detail. We find that the effective charge extracted in the shot noise regime in the weak backscattering limit depends on the noise frequency ω relative to v_F/gL, where v_F is the Fermi velocity, g the Tomonaga Luttinger interaction parameter, and L the length of the wire [2]. The excess noise is finite even for frequencies larger than the applied voltage, which is a signature of correlation effects.

[1] F. Dolcini, H. Grabert, I. Safi, and B. Trauzettel, Phys. Rev. Lett. 91, 266402 (2003).

[2] B. Trauzettel, I. Safi, F. Dolcini, and H. Grabert, Phys. Rev. Lett. 92, 226405 (2004).