Geometry-dependent critical currents in superconducting nanocircuits
By J. Clem, K. Berggren. 2011
247 citations recorded by the source corpus.
In this paper, we calculate the critical currents in thin superconducting strips with sharp right-angle turns, 180? turnarounds, and more complicated geometries, where all the line widths are much smaller than the Pearl length ?=2?2/d. We define the critical current as the current that reduces the Gibbs-free-energy barrier to zero. We show that current crowding, which occurs whenever the current rounds a sharp turn, tends to reduce the critical current, but we also show that when the radius of curvature is less than the coherence length, this effect is partially compensated by a radius-of-curvature effect. We propose several patterns with rounded corners to avoid critical-current reduction due to current crowding. These results are relevant to superconducting nanowire single-photon detectors, where they suggest a means of improving the bias conditions and reducing dark counts. These results also have relevance to normal-metal nanocircuits, as these patterns can reduce the electrical resistance, electromigration, and hot spots caused by nonuniform heating.
Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics
View Paper: https://www.semanticscholar.org/paper/256813e2f79fb7356f23dd2dd38fccf99d7e4541
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In Atomic and Molecular Physics, and Optics
In Condensed Matter Physics
Citations in the corpus
- Superconducting nanowire single-photon detectors for quantum information (2020, background): “Applied Physics Letters 2012, 100(18), 182602 [71] Clem J R & Berggren K K.”
- Superconducting nanowire single-photon detectors: A perspective on evolution, state-of-the-art, future developments, and applications (2021, methodology): “64–66; this current crowding issue can be addressed by optimizing the bend geometry 67 or with spiral SNSPDs. 68 As for the absorption efficiency, the optical absorption of typical superconductors used for SNSPD fabrication has been studied, 69 and the polarization dependence of SDE and nanowire…”