Quantum dot between two superconductors
Department of Physics, Ben-Gurion University of the Negev
2 Forschungszentrum Karlsruhe, Institut für Nanotechnologie 76021 Karlsruhe, Germany
3 I. E. Tamm Department of Theoretical Physics, P. N. Lebedev Physics Institute 117924 Moscow, Russia
Accepted: 30 March 2001
Novel effects emerge from an interplay between multiple Andreev reflections and Coulomb interaction in a quantum dot coupled to superconducting leads and subject to a finite potential bias V. Combining an intuitive physical picture with a rigorous path integral formalism, we evaluate the current I through the dot and find that the interaction shifts the subharmonic pattern of the I-V curve toward higher V. For a sufficiently strong interaction the subgap current (at ) is virtually suppressed.
PACS: 72.10.-d – Theory of electronic transport; scattering mechanisms / 71.27.+a – Strongly correlated electron systems; heavy fermions / 74.40.+k – Fluctuations (noise, chaos, nonequilibrium superconductivity, localization, etc.)
© EDP Sciences, 2001