Regensburg 2004 – wissenschaftliches Programm
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SYSN: Quantum Shot Noise in Nanostructures
SYSN 1: Quantum Shot Noise in Nanostructures
SYSN 1.2: Hauptvortrag
Montag, 8. März 2004, 14:00–14:30, H1
Mesoscopic transition in the shot noise of diffusive SNS junctions — •Francois Lefloch1, Christian Hoffmann1, Marc Sanquer1, and Bernard Pannetier2 — 1Département de Recherche Fondamentale sur la Matière Condensée/SPSMS/LCP, CEA/Grenoble, 17 rue des Martyrs, 38054 Grenoble cedex 09, France — 2Centre de Recherches sur les Très Basses Températures-C.N.R.S. associated to Université Joseph Fourier, 25 rue des Martyrs, 38042 Grenoble, France
We experimentally investigated the current noise in short diffusive Superconductor/Normal metal/Superconductor junctions over a large range of energy that covers the regimes of coherent and incoherent multiple Andreev reflections. The transition between these two regimes, occurs at the Thouless energy where a pronounced minimum in the current noise density is observed. Above the Thouless energy, in the regime of incoherent multiple Andreev reflections, the noise is very much enhanced compared to a normal junction and grows linearly with the bias voltage. Semi-classical theory describes accurately the experimental results over the entire temperature range, but only if we take into account the voltage dependence of the resistance which reflects the proximity effect. Below the Thouless energy, the shot noise diverge as 1/eV and may indicate the coherent transfer of multiple charges.