The excitation spectrum of mesoscopic proximity structures
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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- W. Belzig and C. Bruder, Physikalische Blätter, May 2000.Google Scholar
- D. Saint-James, Journal de Phys. 25, 899 (1964).Google Scholar
- S. Pilgram, Diplomarbeit, Universität Basel, 2000.Google Scholar
- A. Atland, B. D., Simons, D. Taras-Semchuk, cond-mat/9807371.Google Scholar
- S. Pilgram, W. Belzig, and C. Bruder, Physica B, April 2000.Google Scholar