Current-voltage characteristics of NSS transistors

An interesting device to probe the coherent superposition of charge states in superconducting tunnel junctions is the normal-superconductor-superconductor (NSS) transistor where the SS junction is coupled to a normal lead. This system is particularly promising for an investigation of the interplay of coherence in the SS junction and the decoherence due to dissipative electron transitions: in the low-voltage regime Andreev reflection is the dominant transport mechanism, whereas at higher transport voltages Josephson-quasiparticle processes become possible. (C) 2000 Published by Elsevier Science B.V. All rights reserved.