Observation of thermally excited charge transport modes in a superconducting single-electron transistor
Department of Physics, University of Jyväskylä,
P.O. Box 35, FIN-40351 Jyväskylä, Finland
2 Nuclear Physics Institute, Moscow State University - Moscow 119899 GSP, Russia
Accepted: 27 June 1997
Experiments on a superconducting single-electron transistor are reported. A new structure in the current-voltage characteristics at subgap voltages was observed when temperature was not too low as compared to the superconducting transition temperature Tc of the sample. The strength of the anomalies increases exponentially with temperature. The dominating features arise from matching of singularities in the density of states on two sides of a tunnel junction, and from the Josephson-quasiparticle cycle. Thermal excitations are essential for the former process, and they also make the latter process possible at low voltages.
PACS: 73.23.Hk – Coulomb blockade; single-electron tunneling / 74.50.+r – Proximity effects, weak links, tunneling phenomena, and Josephson effects
© EDP Sciences, 1997