Enhancement of critical current density in a superconducting NbSe₂ step junction

We investigate the transport properties of a NbSe₂ nanodevice consisting of a thin region, a thick region and a step junction. We find the critical current density has similar values for both the thin and thick regions away from the junction, while the critical current density of the thin region of the junction increases to approximately 1.8 times as compared with the values obtained for the other regions. We attribute such an enhancement of critical current density to the strong vortex pinning at the surface step.