The Vortex State and Josephson Critical Current of a Diffusive SNS Junction
نویسندگان
چکیده
We study theoretically the electronic and transport properties of a diffusive superconductor-normal metal-superconductor (SNS) junction in the presence of a perpendicular magnetic field. We show that the field dependence of the critical current crosses over from the well-known Fraunhofer pattern in wide junctions to a monotonic decay when the width of the normal wire is smaller than the magnetic length ξH = √Φ0/H , where H is the magnetic field and Φ0 the flux quantum. We demonstrate that this behavior is intimately related to the appearance of a linear array of vortices in the middle of the normal wire, the properties of which are very similar to those in the mixed state of a type II superconductor. This novel vortex structure is also manifested in a strong modulation of the local density of states along the transversal dimension, which can be measured with existing experimental techniques. PACS 74.45.+c · 74.50.+r · 74.25.Qt
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