Fractional-flux Little-Parks resistance oscillations in disordered superconducting Au$_{0.7}$In$_{0.3}$ cylinders

TL;DR

This study observes fractional-flux resistance oscillations in disordered AuIn superconducting cylinders, revealing a transition from standard $h/2e$ to $h/4e$ oscillations at lower temperatures, indicating novel quantum effects.

Contribution

It reports the first observation of $h/4e$ resistance oscillations in disordered superconducting cylinders, expanding understanding of flux quantization in such systems.

Findings

Resistance oscillates with $h/2e$ at high temperatures.

Splitting of resistance peaks occurs at lower temperatures.

Emergence of $h/4e$ oscillations suggests new free energy minima.

Abstract

Resistance of disordered superconducting Au$_{0.7}$In$_{0.3}$ cylindrical films was measured as a function of applied magnetic field. In the high-temperature part of the superconducting transition regime, the resistance oscillated with a period of $h/2e$ in the unit of the enclosed magnetic flux. However, at lower temperatures, the resistance peaks split. We argue that this splitting is due to the emergence of an oscillation with a period of $h/4e$, half of the flux quantum for paired electrons. The possible physical origin of the $h/4e$ resistance oscillation is discussed in the context of new minima in the free energy of a disordered superconducting cylinder.