Josephson coupling through a quantum dot
Abstract
We derive, via fourthorder perturbation theory, an expression for the Josephson current through a gated interacting quantum dot. We analyze our expression for two different models of the superconductordotsuperconductor (SDS) system. When the matrix elements connecting dot and leads are featureless constants, we compute the Josephson coupling J_{c} as a function of the gate voltage and Coulomb interaction. In the limit of a diffusive dot, we compute the probability distribution P(J_{c}) of Josephson couplings. In both cases, π junction behavior (J_{c}<0) is possible, and is not simply dependent on the parity of the dot occupancy.
 Publication:

Physical Review B
 Pub Date:
 December 2001
 DOI:
 10.1103/PhysRevB.64.233301
 arXiv:
 arXiv:condmat/0011201
 Bibcode:
 2001PhRvB..64w3301R
 Keywords:

 74.50.+r;
 73.40.Gk;
 Tunneling phenomena;
 point contacts weak links Josephson effects;
 Tunneling;
 Condensed Matter  Mesoscale and Nanoscale Physics;
 Condensed Matter  Superconductivity
 EPrint:
 9 pages