Dissociation of vortex stacks into fractional-flux vortices.
We discuss the zero field superconducting phase transition in a finite system of magnetically coupled superconducting layers. Transverse screening is modified by the presence of other layers resulting in topological excitations with fractional flux. Vortex stacks trapping a full flux and present at any finite temperature undergo a dissociation transition which corresponds to the depairing of fractional-flux vortices in individual layers. We propose an experiment with a bilayer system allowing us to identify the dissociation of bound vortex molecules.
De Col
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Theoretische Physik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
Geshkenbein
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Blatter
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