Josephson current through a T-shaped double quantum dots: π-junction transition and interdot antiferromagnetic correlations

By means of the exact diagonalization approach, the Josephson current in a T-shaped double quantum dot structure is theoretically investigated. The ground state is obtained within zero bandwidth approximation in which the superconductors are replaced by effective local pairing potentials. It is found that Josephson current can flow through this structure in the presence of various electron correlations. Furthermore, in the half-filled case, a novel 0-pi transition behavior is observed, which arises from the interplay of interdot antiferromagnetic coupling and electron correlations. (C) 2013 Elsevier B.V. All rights reserved.