Geometry-dependent critical currents in superconducting nanocircuits
| Title | Geometry-dependent critical currents in superconducting nanocircuits |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Authors | Clem JR, Berggren KK |
| Journal Title | Physical Review B |
| Volume | 84 |
| Pages | 174510 |
| Date Published | 11 |
| Type of Article | Article |
| ISBN Number | 1098-0121 |
| Accession Number | WOS:000297157500010 |
| Keywords | films, VORTEX |
| Abstract | In this paper, we calculate the critical currents in thin superconducting strips with sharp right-angle turns, 180 degrees turnarounds, and more complicated geometries, where all the line widths are much smaller than the Pearl length Lambda = 2 lambda(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. |
| DOI | 10.1103/PhysRevB.84.174510 |
| Alternate Journal | Phys. Rev. B |
