Geometry-dependent critical currents in superconducting nanocircuits
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 Λ=2λ2/d. We define the critical current as the current that reduces the G...
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| Format: | Article |
| Language: | en_US |
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American Physical Society
2012
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| Online Access: | http://hdl.handle.net/1721.1/69832 https://orcid.org/0000-0001-7453-9031 |
| _version_ | 1826190414203322368 |
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| author | Clem, John R. Berggren, Karl K. |
| author2 | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science |
| author_facet | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Clem, John R. Berggren, Karl K. |
| author_sort | Clem, John R. |
| collection | MIT |
| description | 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 Λ=2λ2/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. |
| first_indexed | 2024-09-23T08:39:54Z |
| format | Article |
| id | mit-1721.1/69832 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:39:54Z |
| publishDate | 2012 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/698322022-09-30T10:20:02Z Geometry-dependent critical currents in superconducting nanocircuits Clem, John R. Berggren, Karl K. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Berggren, Karl K. Berggren, Karl K. 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 Λ=2λ2/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. 2012-03-22T15:36:18Z 2012-03-22T15:36:18Z 2011-11 2011-11 Article http://purl.org/eprint/type/JournalArticle 1098-0121 1550-235X http://hdl.handle.net/1721.1/69832 Clem, John, and Karl Berggren. “Geometry-dependent Critical Currents in Superconducting Nanocircuits.” Physical Review B 84.17 (2011): [27 pages]. https://orcid.org/0000-0001-7453-9031 en_US http://dx.doi.org/10.1103/PhysRevB.84.174510 Physical Review B Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society APS |
| spellingShingle | Clem, John R. Berggren, Karl K. Geometry-dependent critical currents in superconducting nanocircuits |
| title | Geometry-dependent critical currents in superconducting nanocircuits |
| title_full | Geometry-dependent critical currents in superconducting nanocircuits |
| title_fullStr | Geometry-dependent critical currents in superconducting nanocircuits |
| title_full_unstemmed | Geometry-dependent critical currents in superconducting nanocircuits |
| title_short | Geometry-dependent critical currents in superconducting nanocircuits |
| title_sort | geometry dependent critical currents in superconducting nanocircuits |
| url | http://hdl.handle.net/1721.1/69832 https://orcid.org/0000-0001-7453-9031 |
| work_keys_str_mv | AT clemjohnr geometrydependentcriticalcurrentsinsuperconductingnanocircuits AT berggrenkarlk geometrydependentcriticalcurrentsinsuperconductingnanocircuits |