Tuning a Josephson junction through a quantum critical point

J. K. Freericks; B. K. Nikolić; P. Miller

doi:10.1103/PhysRevB.64.054511

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Tuning a Josephson junction through a quantum critical point

J. K. Freericks, B. K. Nikolić, P. Miller

DOI 10.1103/PhysRevB.64.054511 · Physical Review B

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Abstract

We tune the barrier of a Josephson junction through a zero-temperature metal-insulator transition and study the thermodynamic behavior of the junction in the proximity of the quantum-critical point. We examine a short-coherence-length superconductor and a barrier (that is described by a Falicov-Kimball model) using the local approximation and dynamical mean-field theory. The inhomogeneous system is self-consistently solved by performing a Fourier transformation in the planar momentum and exactly inverting the remaining one-dimensional matrix with the renormalized perturbation expansion. Our results show a delicate interplay between oscillations on the scale of the Fermi wavelength and pair-field correlations on the scale of the coherence length, variations in the current-phase relationship, and dramatic changes in the characteristic voltage as a function of the barrier thickness or correlation strength (which can lead to an “intrinsic” pinhole effect).