Can mesoscopic fluctuations reverse the supercurrent through a disordered Josephson junction?
arXiv:cond-mat/0106018 · doi:10.1103/PhysRevB.65.012504
Abstract
We calculate the Josephson coupling energy $U_J(Ï)$ (related to the supercurrent $I=(2e/\hbar) dU_J/dÏ$) for a disordered normal metal between two superconductors with a phase difference $Ï$. We demonstrate that the symmetry of the scattering matrix of non-interacting quasiparticles in zero magnetic field implies that $U_J(Ï)$ has a minimum at $Ï=0$. A maximum (that would lead to a $Ï$-junction or negative superfluid density) is excluded for any realization of the disorder.
2 pages