Vortices and dissipation in a bilayer thin film superconductor

Wei Zhang; H. A. Fertig

doi:10.1103/PhysRevB.71.224514

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Vortices and dissipation in a bilayer thin film superconductor

Wei Zhang, H. A. Fertig

DOI 10.1103/PhysRevB.71.224514 · Physical Review B

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Abstract

Vortex dynamics in a bilayer thin film superconductor are studied through a Josephson-coupled double layer XY model. A renormalization group analysis shows that there are three possible states associated with the relative phase of the layers: a free vortex phase, a logarithmically confined vortex-antivortex pair phase, and a linearly confined phase. The phases may be distinguished by measuring the resistance to counterflow current. For a geometry in which current is injected and removed from the two layers at the same edge by an ideal (dissipationless) lead, we argue that the three phases yield distinct behaviors: metallic conductivity in the free vortex phase, a power law I−V in the logarithmically confined phase, and true dissipationless superconductivity in the linearly confined phase. Numerical simulations of a resistively shunted Josephson junction model reveal size dependencies for the resistance of this system that support these expectations.