Negative superfluid density: Mesoscopic fluctuations and reverse of the supercurrent through a disordered Josephson junction - art. no. 012504

摘要

We calculate the Josephson coupling energy U-J(phi) [related to the supercurrent I = (2e/(h) over bar )dU(J)/dphi] for a disordered normal metal between two superconductors with a phase difference phi. We demonstrate that the symmetry of the scattering matrix of noninteracting quasiparticles in zero magnetic field implies that U-J(phi) has a minimum at phi=0. A maximum (that Would lead to a pi, junction or negative superfluid density) is excluded for an realization of the disorder. [References: 10]