Making superconducting nanocircuits with rounded internal corners will significantly improve performance. Scientists showed this by calculating how circuit geometry impacts current flow. The key is how geometry affects “current crowding”. Crowding can happen when electrical current travels around a sharp corner or hairpin turn much like cars racing on a tight track. The current (like cars) tends to concentrate near the inner edges of sharp turns. By rounding the corners this bottleneck is eased. This work explains reduced critical currents observed in manufactured devices and has important implications for both superconducting and metal film devices, including nanowire single photon detectors and devices that measure extremely small magnetic fields.
J. R. Clem and K. K. Berggren “Geometry-Dependent Critical Currents in Superconducting Nanocircuits” Physical Review B 84 (2011) 174510. DOI 10.1103/PhysRevB.84.174510