Weber blockade in superconducting nanowires

TL;DR

This paper reports the observation of Weber blockade in superconducting aluminum nanowires, where the critical current oscillates with magnetic field due to single vortex addition, acting as quantum dots for vortices.

Contribution

It introduces the concept of Weber blockade in superconducting nanowires, demonstrating vortex quantization effects analogous to Coulomb blockade in quantum dots.

Findings

Critical current oscillates with magnetic field in nanowires.

Oscillations correspond to adding a single vortex.

Nanowires behave as quantum dots for vortices.

Abstract

We have measured the critical current as a function of magnetic field in short and narrow superconducting aluminum nanowires. In the range of magnetic fields in which vortices can enter a nanowire in a single row, we find regular oscillations of the critical current as a function of magnetic field. The oscillations are found to correspond to adding a single vortex to the nanowire, with the number of vortices on the nanowire staying constant within each period of the oscillation. This effect can be thought of as a Weber blockade, and the nanowires act as quantum dots for vortices, analogous to the Coulomb blockade for electrons in quantum dots.