Superconductive proximity effect in interacting disordered conductors
Abstract
We present a general theory of the superconductive proximity effect in disordered normalmetalsuperconducting (NS) structures, based on the recently developed [M. V. Feigel'man et al., Phys. Rev. B 61, 12 361 (2000)] Keldysh action approach. In the case of the absence of an interaction in the normal conductor we reproduce known results for the Andreev conductance G_{A} at an arbitrary relation between the interface resistance R_{T} and the diffusive resistance R_{D}. In twodimensional NS systems, the electronelectron interaction in the Cooper channel of a normal conductor is shown to strongly affect the value of G_{A} as well as its dependence on temperature, voltage, and magnetic field. In particular, an unusual maximum of G_{A} as a function of temperature and/or magnetic field is predicted for some range of parameters R_{D} and R_{T}. The Keldysh action approach makes it possible to calculate the full statistics of charge transfer in such structures. As an application of this method, we calculate the noise power of an NS contact as a function of voltage, temperature, magnetic field, and frequency for arbitrary Cooper repulsion in the normal metal and arbitrary values of the ratio R_{D}/R_{T}.
 Publication:

Physical Review B
 Pub Date:
 April 2001
 DOI:
 10.1103/PhysRevB.63.134507
 arXiv:
 arXiv:condmat/0008463
 Bibcode:
 2001PhRvB..63m4507S
 Keywords:

 74.40.+k;
 74.50.+r;
 72.10.Bg;
 Fluctuations;
 Tunneling phenomena;
 point contacts weak links Josephson effects;
 General formulation of transport theory;
 Condensed Matter  Superconductivity;
 Condensed Matter  Mesoscale and Nanoscale Physics
 EPrint:
 RevTeX, 28 pages, 18 PostScript figures