The excitation spectrum of mesoscopic proximity structures

  • S. Pilgram
  • W. Belzig
  • C. Bruder
Hybrid Quantum Systems
Part of the Advances in Solid State Physics book series (ASSP, volume 40)


We investigate one aspect of the proximity effect, viz., the local density of states of a superconductor-normal metal sandwich. In contrast to earlier work, we allow for the presence of an arbitrary concetration of impurities in the structure. The superconductor induces a gap in the normal metal spectrum that is proportional to the inverse of the elastic mean free path l for rather clean systems. For a mean free path much shorter than the thickness of the normal metal, we find a gap size proportional to l that approaches the behavior predicted by the Usadel equation (diffusive limit). We also discuss the influence of interface and surface roughness, the conseqeunces of a non-ideal transmittivity of the interface, and the dependence of our results on the choice of the model of impurity scattering.


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Copyright information

© Friedr. Vieweg & Sohn Verlagsgesellschaft mbH 2000

Authors and Affiliations

  • S. Pilgram
    • 1
  • W. Belzig
    • 2
  • C. Bruder
    • 1
  1. 1.Departement Physik und AstronomieUniversität BaselBaselSwitzerland
  2. 2.Theoretical Physics GroupDelft University of TechnologyGA DelftThe Netherlands

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