Effect of Andreev Processes on the Goos-H\"anchen (GH) shift in the Graphene-Superconductor-Graphene (GSG) junctions

Abstract

In this article, we study the transport properties of Graphene-Superconductor-Graphene (GSG) heterojunction where the superconducting region is created in the middle of a graphene sheet, as contrasted to widely studied transport properties through a Superconductor-Graphene-Superconductor (SGS) type of Josephson junction. We particularly analyse in detail the Goos-H\"anchen shift of the electron and the hole at the GS interface in such a junction, due to normal as well as Andreev reflection, using a transfer matrix-based approach. Additionally, we evaluate the normalised differential conductance as a function of bias voltage that characterises the transport through such junction and point out how they are influenced by Andreev and normal reflection. In the subsequent parts of the article we demonstrate how the GH shift for both electron and hole changes with the width of the superconducting region. The behavior of the differential conductance in such junctions as a function of the bias voltage in the region, dominated by Andreev and normal reflection, is also presented and analysed.