Single-walled carbon nanotube weak links: from Fabry-Pérot to Kondo regime

Abstract

We have investigated proximity-induced supercurrents in single-walled carbon nanotubes in the Kondo regime and compared them with supercurrents obtained on the same tube with Fabry-Pérot resonances. Our data display a wide distribution of Kondo temperatures \emph{$T_K$} = 1 - 14 K, and the measured critical current $I_{CM}$ vs. \emph{$T_K$} displays two distinct branches; these branches, distinguished by zero-bias splitting of the normal-state Kondo conductance peak, differ by an order of magnitude at large values of $T_K$. Evidence for renormalization of Andreev levels in Kondo regime is also found.

4 pages, 4 figures