Coherent current transport in wide ballistic Josephson junctions

TL;DR

This paper investigates how coherent current transport in wide ballistic Josephson junctions is affected by junction length, revealing shifts in subharmonic gap structures and excess current reduction explained by Andreev resonances.

Contribution

It combines experimental data with a theoretical model to explain length-dependent changes in current transport via Andreev resonances in ballistic Josephson junctions.

Findings

Subharmonic gap structure shifts to lower voltages with increased junction length.

Excess current decreases as junction length increases.

Transport is explained through Andreev resonances.

Abstract

We present an experimental and theoretical investigation of coherent current transport in wide ballistic superconductor-two dimensional electron gas-superconductor junctions. It is found experimentally that upon increasing the junction length, the subharmonic gap structure in the current-voltage characteristics is shifted to lower voltages, and the excess current at voltages much larger than the superconducting gap decreases. Applying a theory of coherent multiple Andreev reflection, we show that these observations can be explained in terms of transport through Andreev resonances.