Long-range coherence and mesoscopic transport in N–S metallic structures

✍ Scribed by Hervé Courtois; Philippe Gandit; Bernard Pannetier; Dominique Mailly

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 349 KB
• Volume: 25
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1999.0711

✦ Synopsis

We review the mesoscopic transport in a diffusive proximity superconductor made of a normal metal (N) in metallic contact with a superconductor (S). The Andreev reflection of electrons on the N-S interface is responsible for the diffusion of electron pairs in N. Superconducting-like properties are induced in the normal metal. In particular, the conductivity of the N metal is locally enhanced by the proximity effect. A re-entrance of the metallic conductance occurs when all the energies involved (e.g. temperature and voltage) are small. The relevant characteristic energy is the Thouless energy which is divided by the diffusion time for an electron travelling throughout the sample. In loopshaped devices, a 1/T temperature-dependent oscillation of the magnetoresistance arises with a large amplitude from the long-range coherence of low-energy pairs.