Josephson current in strongly correlated double quantum dots.
We study the Josephson current through a serial double quantum dot and the associated 0-π transitions which result from the subtle interplay between the superconductivity, the Kondo physics, and the interdot superexchange interaction. The competition between them is examined by tuning the relative strength Δ/T(K) of the superconducting gap and the Kondo temperature, for different strengths of the superexchange coupling determined by the interdot tunneling t relative to the level broadening Γ. We find strong renormalization of t, a significant role of the superexchange coupling J, and a rich phase diagram of the 0 and π-junction regimes. In particular, when both the superconductivity and the exchange interaction compete with the Kondo physics (Δ∼J∼T(K)), there appears an island of π' phase at large values of the superconducting phase difference.
Zitko
Rok
R
J. Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
Lee
Minchul
M
López
Rosa
R
Aguado
Ramón
R
Choi
Mahn-Soo
MS