Edge Tunneling of Vortices in Superconducting Thin Films

TL;DR

This paper derives an explicit formula for quantum vortex tunneling at the edge of superconducting films, revealing a decay mechanism for supercurrents that complements bulk vortex nucleation, with implications for superconductor stability.

Contribution

It introduces a novel edge-tunneling formula for vortices in thin superconducting films, extending previous bulk nucleation models to include edge effects at zero temperature.

Findings

Derived explicit tunneling rate formula for edge vortices.

Compared edge tunneling with bulk nucleation, showing both can cause supercurrent decay.

Numerical estimates support the significance of edge tunneling in superconductor dynamics.

Abstract

We investigate the phenomenon of the decay of a supercurrent due to the zero-temperature quantum tunneling of vortices from the edge in a thin superconducting film in the absence of an external magnetic field. An explicit formula is derived for the tunneling rate of vortices, which are subject to the Magnus force induced by the supercurrent, through the Coulomb-like potential barrier binding them to the film's edge. Our approach ensues from the non-relativistic version of a Schwinger-type calculation for the decay of the 2D vacuum previously employed for describing vortex-antivortex pair-nucleation in the bulk of the sample. In the dissipation-dominated limit, our explicit edge-tunneling formula yields numerical estimates which are compared with those obtained for bulk-nucleation to show that both mechanisms are possible for the decay of a supercurrent.