Magnetic Flux Periodic Response of Nano-perforated Ultrathin Superconducting Films

TL;DR

This study investigates how nano-perforations in ultrathin superconducting films induce a magnetic flux periodic response, revealing different fluctuation regimes near the superconductor-insulator transition.

Contribution

It demonstrates phase-sensitive magnetic response in nano-perforated ultrathin superconducting films and distinguishes fluctuation regimes through resistive transition measurements.

Findings

Flux periodic response observed in patterned films.

Amplitude fluctuations dominate near the superconductor-insulator transition.

Response varies with transition temperature.

Abstract

We have patterned a hexagonal array of nano-scale holes into a series of ultrathin, superconducting Bi/Sb films with transition temperatures 2.65 K $<T_{co} < $5 K. These regular perforations give the films a phase-sensitive periodic response to an applied magnetic field. By measuring this response in their resistive transitions, $R(T)$, we are able to distinguish regimes in which fluctuations of the amplitude, both the amplitude and phase, and the phase of the superconducting order parameter dominate the transport. The portion of $R(T)$ dominated by amplitude fluctuations is larger in lower $T_{co}$ films and thus, grows with proximity to the superconductor to insulator transition.