Giant Conductance Oscillations In Mesoscopic Andreev Interferometers

TL;DR

This paper investigates the conductance oscillations in mesoscopic Andreev interferometers, showing how barriers and disorder can significantly enhance oscillation amplitude and alter phase dependence.

Contribution

It demonstrates that placing a normal barrier or inducing disorder can produce giant conductance oscillations, surpassing previous experimental observations.

Findings

Barrier placement enhances oscillation amplitude significantly.

Disorder can break sum rules, leading to giant oscillations.

Zero phase conductance minimum is observed without zero phase inter-channel scattering.

Abstract

We analyze the electrical conductance $G(\phi)$ of a two-dimensional, phase coherent structure in contact with two superconductors, which is known to be an oscillatory function of the phase difference $\phi$ between the superconductors. It is predicted that for a metallic sample, the amplitude of oscillation is enhanced by placing a normal barrier at the interface and that, by tuning the strength of the barrier, can be orders of magnitude greater than values observed in recent experiments. Giant oscillations can also be obtained without a barrier, provided a crucial sum rule is broken. This can be achieved by disorder induced normal scattering. In the absence of zero phase inter-channel scattering, the conductance possesses a zero phase minimum.