Nonequilibrium Josephson effect in short-arm diffusive SNS interferometers

TL;DR

This paper investigates the non-equilibrium Josephson effect and phase-dependent conductance in short-arm diffusive SNS interferometers, revealing how interface transparency and voltage influence Josephson current behavior and conductance features.

Contribution

It provides new insights into the interplay of dissipative and Josephson currents, especially regarding current inversion and conductance peaks in non-equilibrium conditions.

Findings

Josephson current suppression at large voltages in transparent interfaces

Current inversion possible with resistive interfaces within certain voltage ranges

Distinct conductance peaks at the bulk and proximity gap energies

Abstract

We study non-equilibrium Josephson effect and phase-dependent conductance in three-terminal diffusive interferometers with short arms. We consider strong proximity effect and investigate an interplay of dissipative and Josephson currents co-existing within the same proximity region. In junctions with transparent interfaces, the suppression of the Josephson current appears at rather large voltage, $eV\sim \Delta$, and the current vanishes at $eV\geq\Delta$. Josephson current inversion becomes possible in junctions with resistive interfaces, where the inversion occurs within a finite interval of the applied voltage. Due to the presence of considerably large and phase-dependent injection current, the critical current measured in a current biased junction does not coincide with the maximum Josephson current, and remains finite when the true Josephson current is suppressed. The voltage dependence of the conductance shows two pronounced peaks, at the bulk gap energy, and at the proximity gap energy; the phase oscillation of the conductance exhibits qualitatively different form at small voltage $eV<\Delta$, and at large voltage $eV>\Delta$.