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Can mesoscopic fluctuations reverse the supercurrent through a disordered Josephson junction?

M. Titov·Ph. Jacquod·C. W. J. Beenakker
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Abstract

We calculate the Josephson coupling energy $U_J(ϕ)$ (related to the supercurrent $I=(2e/\hbar) dU_J/dϕ$) for a disordered normal metal between two superconductors with a phase difference $ϕ$. We demonstrate that the symmetry of the scattering matrix of non-interacting quasiparticles in zero magnetic field implies that $U_J(ϕ)$ has a minimum at $ϕ=0$. A maximum (that would lead to a $π$-junction or negative superfluid density) is excluded for any realization of the disorder.

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M. Titov, Ph. Jacquod, C. W. J. Beenakker. 2001-06-01. Can mesoscopic fluctuations reverse the supercurrent through a disordered Josephson junction?. https://doi.org/10.1103/physrevb.65.012504

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