Regensburg 2004 – scientific programme

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TT: Tiefe Temperaturen

TT 27: Nanoelektronik III: Molekulare Elektronik

TT 27.11: Talk

Thursday, March 11, 2004, 12:30–12:45, H19

Transport through a Carbon Nanotube with Superconducting Contacts — •Wolfgang Belzig, Mark Buitelaar, Thomas Nussbaumer, Christoph Bruder, and Christian Schöneberger — Universität Basel, Klingelbergstr. 82, 4056 Basel, Schweiz

We report on experimental and theoretical studies of transport through multi-walled carbon nanotubes strongly coupled to superconducting leads. In the normal state of the leads the conductance displays a Kondo behaviour for odd numbers of electrons on the nanotube dot. If superconductivity is turned on, the transport characteristic changes dramatically. A large zero bias conductance (with G≫ 2e²/h) and a strongly nonlinear differential conductance are observed. Both effects depend on the gate voltage. We explain the experimental observations theoretically by a subtle interplay between Kondo physics and proximity effect on the dot. Multiple Andreev reflections play a key-role to explain the features seen in the differential conductance.