Nanoscale thermal effect induced the evolution of electric transport of Nb bridges

Abstract We reported the evolution of electric transport of Nb bridges based on nanoscale thermal effect created by Nano Laser Direct Writing (NLDW) on Nb films. The laser-Nb films interaction was investigated experimentally and by simulation. We demonstrate the laser parameters such as irradiation power and interaction time to manipulate the electric transport of Nb bridges such as critical current and transition temperature by simulation, which is align with electron probe microanalyzer results. Base on the optimized laser parameters, we realize the continually changes of current-voltage characteristics via increasing irradiation power. Furthermore, Nb bridges after laser irradiation show the oscillations of critical current via applying coil current as magnetic perpendicular to the Nb bridges, which is similar to Fraunhofer pattern as Josephson junction under magnetic. In this case, NLDW shows the potential to manipulate electrical performances, which could be used to trim tri-layer junctions, tune shunt resistors, or adjust critical currents or even induce Josephson junction in-situ by further shrinking the laser spot.