Resistance of superconductor-normal metal-superconductor junctions

TL;DR

This paper investigates how the conductance in superconductor-normal metal-superconductor junctions varies with the phase of the superconducting order parameter, especially when the normal region is large and the critical current is very small.

Contribution

It reveals the phase-dependent conductance behavior in long junctions with small critical currents, highlighting conditions for different oscillation periods.

Findings

Conductance depends on the phase of the superconducting order parameter.

Oscillation period can be either π or 2π depending on system parameters.

Significant phase dependence occurs even when the normal region exceeds the coherence length.

Abstract

It is shown that the conductance of a superconductor-normal metal-superconductor junction can exhibit a significant dependence on the phase of the superconducting order parameter in the situation when the size of the normal region of the junction is much larger than the normal metal coherence length and the critical current of the junction is already exponentially small. The period of the conductance oscillations as a function of the phase can be equal to $\pi$ or $2\pi$ depending on parameters of the system.