Proximity Induced Superconductivity and Multiple Andreev Reflections in Few-Layer-Graphene

TL;DR

This study explores how superconductivity can be induced in few-layer-graphene through proximity effects, revealing multiple Andreev reflections and providing insights into superconducting transport in graphene-based devices.

Contribution

It demonstrates proximity-induced superconductivity and multiple Andreev reflections in few-layer-graphene with a novel device fabrication method.

Findings

Proximity-induced superconductivity observed below 1K.

Multiple Andreev reflection signatures detected.

Large differential resistance drop at low bias.

Abstract

We have investigated electronic transport of few-layer-graphene (FLG) connected to superconducting electrodes. The device is prepared by mechanical exfoliation of graphite. A small mesa of FLG is placed on the surface of an insulating Alumina layer over silicon substrate, and is connected with two tungsten electrodes, separated by 2.5 microns, grown by focused ion beam. While tungsten electrodes are superconducting below 4 K, proximity induced superconductivity in FLG is observed below 1K with a large differential resistance drop at low bias. Signatures of multiple Andreev reflections are observed as peaks located at voltages corresponding to sub-multiple values of the superconducting gap of the electrodes.