Dresden 2003 – scientific programme
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TT: Tiefe Temperaturen
TT 1: Mesoskopische Systeme I
TT 1.8: Talk
Monday, March 24, 2003, 11:30–11:45, HSZ03
Phase sensitive shot noise in an Andreev interferometer — •Wolfgang Belzig1, Yuli V. Nazarov2, Bertrand Reulet3, Alexander A. Kozhevnikov3, and Daniel E. Prober3 — 1Universität Basel, Basel, Schweiz — 2TU Delft, Delft, Niederlande — 3Yale University, New Haven, USA
We investigate nonequilibrium noise in a diffusive Andreev interferometer, in which currents emerging from two Normal metal/Superconductor (N-S) interfaces can interfere. We find theoretically and experimentally a modulation of the shot noise when the phase difference between the two N-S interfaces is varied by a magnetic flux [1]. This is the first experimental observation of a phase sensitive shot noise. The effective charge (i.e. the derivative of the current noise with respect to the current, appropriately normalized) inferred from the shot noise measurement is close to qeff = 2e but shows phase-dependent deviations from 2e at finite energy, which we interprete as due to pair correlations. The experimental data are in good agreement with theoretical predictions based on an extended Keldysh Green’s function approach [2].
[1] B. Reulet, A.A. Kozhevnikov, D.E. Prober, W. Belzig, and Yu.V. Nazarov, to be published in Phys. Rev. Lett.
[2] W. Belzig and Yu. V. Nazarov, Phys. Rev. Lett. 87, 067006 (2001).