Berlin 2008 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 21: Transport: Graphene and Carbon Nanotubes

TT 21.12: Talk

Tuesday, February 26, 2008, 18:45–19:00, EB 202

Supercurrent through carbon nanotubes with Nb contacts — •Emiliano Pallecchi, Markus Gaass, and Christoph Strunk — University of Regensburg, Germany

We report on low temperature transport measurements on a multiwall carbon nanotube (MWNT) coupled to niobium leads. We used a very careful filtering scheme which is essential in order to measure small supercurrents. To provide damping at the plasma frequency, we used on chip resistors and capacitors. Depending on the gate voltages the sample shows both, proximity induced supercurrent and Coulomb blockade. The supercurrent showed narrow resonances corresponding to the Coulomb resonances at lower transmission. We found supercurrents up to 30nA, which is, to our knowledge, this is the highest value observed so far. At very low temperature the IV characteristics are characterized by hysteretic switching; when increasing T the hysteresis is gradually suppressed. In the hysteretic regime, we have also measured switching histograms to gain further information on the switching mechanism.