» Investigating Innovative Superconducting Materials: Reaching for Room-Temperature Superconductivity

Our recent interest was in single-flux quantum (SFQ) physics in weakly-coupled superconductor-normal metal-superconductor (SNS) Josephson junctions. We modeled these junctions is a planar geometry, where current flows in along one superconducting bank, moves along it, while crossing the initially normal region, which is converted in a weaker superconductor by proximity effect, and flows back and out along the next bank.

Abrikosov vortices/single flux quanta are being generated at the applied DC current, if its value is above the certain threshold. These vortices move and exit the junction, and generate a voltage pulse at the moment of escape. Green arrows indicate the electric vector.

Reversely, if the junction is biased below the critical current value, then a pulse generated by an SFQ signal can launch an Abrikosov vortex, which will move along the junction and exit it, emitting the same type of signal which initiated it.