Geometry Dependent Superconductive Transition of Nb Nanostructures

Recently, superconducting nanostructures gained particular attention due to the visualisation of some intriguing phenomena, such as phase fluctuations, quantum phase slip, shape resonance in critical temperature, allowing the definition of a tailored superconducting nanodevice with the desired superconducting features, quantum phenomena. A deep investigation into the relationship between superconductivity, low dimensionality, quantum phenomena should be performed, in order to explain the emergence mechanism of these effects in nanostructures, how superconductivity is affected. In the following, we report on the investigation of the superconductive transition in triangular-shaped Nb pads connecting a Nb nanostripe. As revealed by R vs T curves, and the superconductive transition is observed to be characterised by two regions: i) a first smooth and wide transition reflecting the continuous reduction in the width of the Nb triangular pads that progressively experience superconductive transition, and ii) a more abrupt transition reflecting the transition of the Nb nanostripe. This work could pave the way concerning the realisation of Nb nanostructures with tunable critical temperature, transition width, and slope.