Josephson Effect in a Coulomb-blockaded SINIS Junction
P. M. Ostrovsky, M. V. Feigel'man
L. D. Landau Institute for Theoretical Physics RAS, 119334 Moscow, Russia
PACS: 73.21.-b, 74.45.+c, 74.50.+r
The problem of Josephson current through Coulomb-blocked nanoscale
superconductor-normal-superconductor structure with tunnel contacts is
reconsidered. Two different contributions to the phase-biased supercurrent
are identified, which are dominant in the limits of weak and
strong Coulomb interaction. Full expression for the free energy valid at
arbitrary Coulomb strength is found. The current derived from this free
energy interpolates between known results for weak and strong Coulomb
interaction as phase bias changes from 0 to π. In the broad range of
Coulomb strength the current-phase relation is substantially non-sinusoidal
and qualitatively different from the case of semi-ballistic SNS junctions.
Coulomb interaction leads to appearance of a local minimum in the current at
some intermediate value of phase difference applied to the junction.