Density of states in a mesoscopic SNS junction

  • P. M. Ostrovsky
  • M. A. Skvortsov
  • M. V. Feigel’man
Condensed Matter

Abstract

The semiclassical theory of proximity effects predicts a gap Eg∼ℏD/L2 in the excitation spectrum of a long diffusive superconductor/normal-metal/superconductor (SNS) junction. Mesoscopic fluctuations lead to anomalously localized states in the normal part of the junction.As a result, a nonzero, yet exponentially small, density of states (DOS) appears at energies below Eg. In the framework of the supermatrix nonlinear σ model, these prelocalized states are due to the instanton configurations with broken supersymmetry. The exact result for the DOS near the semiclassical threshold is found, provided the dimensionless conductance of the normal part GN is large. The case of poorly transparent interfaces between the normal and superconductive regions is also considered. In this limit, the total number of subgap states may be large.

PACS numbers

73.21.−b 74.50.+r 74.80.Fp 

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Copyright information

© MAIK "Nauka/Interperiodica" 2002

Authors and Affiliations

  • P. M. Ostrovsky
    • 1
  • M. A. Skvortsov
    • 1
  • M. V. Feigel’man
    • 1
  1. 1.Landau Institute for Theoretical PhysicsRussian Academy of SciencesMoscowRussia

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