Kondo resonance in a nanotube quantum dot coupled to a normal and a superconducting lead

M. R. Graeber; T. Nussbaumer; W. Belzig; T. Kontos; C. Schoenenberger

paper

Kondo resonance in a nanotube quantum dot coupled to a normal and a superconducting lead

arXiv:cond-mat/0406638

Abstract

We report on electrical transport measurements through a carbon nanotube quantum dot coupled to a normal and a superconducting lead. The ratio of Kondo temperature and superconducting gap $T_{K} /Δ$ is identified to govern the transport properties of the system. In the case of $T_{K} < Δ$ the conductance resonance splits into two resonances at $\pm Δ$ . For the opposite scenario $T_{K} > Δ$ the conductance resonance persists, however the conductance is not enhanced compared to the normal state due to a relative asymmetry of the lead-dot couplings. Within this limit the data is in agreement with a simple model of a resonant SN-interface.

4 pages, 2 figures. submitted to the Proc. Rencontres de Moriond on Quantum Information and Decoherence in Nanosystems 2004