Europhys. Lett.
Volume 61, Number 6, March 2003
Page(s) 824 - 830
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 March 2003
DOI: 10.1209/epl/i2003-00308-1
Europhys. Lett., 61 (6) , pp. 824-830 (2003)

Spectral flow in superconducting point contacts

N. B. Kopnin1, 2, 3 and V. M. Vinokur3

1  Low Temperature Laboratory, Helsinki University of Technology FIN-02015, Finland
2  L. D. Landau Institute for Theoretical Physics - 117940 Moscow, Russia
3  Argonne National Laboratory - Argonne, IL 60439, USA

(Received 6 August 2002; accepted in final form 17 January 2003)

We find that multiple Andreev reflections mediating the transport in superconducting point contacts are strongly affected by a small amount of impurities in the area of the contact. We also argue that the model based on Zener transitions within independent conducting channels is not suitable for kinetic processes in multichannel contacts.

74.80.Fp - Point contacts; SN and SNS junctions.
73.23.-b - Electronic transport in mesoscopic systems.
73.63.Rt - Nanoscale contacts.

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