Andreev transport in two-dimensional normal-superconducting systems in strong magnetic fields

TL;DR

This paper investigates how strong magnetic fields influence Andreev transport in 2D normal-superconducting systems within the Quantum Hall regime, focusing on edge state mixing and conductance fluctuations.

Contribution

It provides a detailed analysis of Andreev processes and conductance behavior in 2D NS systems under strong magnetic fields, including effects of edge state mixing and spectral types.

Findings

Magnetoconductance is affected by edge state mixing at NS interfaces.

Conductance fluctuations depend on the number of conducting channels.

Both quadratic and Dirac-like spectra are analyzed for transport properties.

Abstract

The conductance in two-dimensional (2D) normal-superconducting (NS) systems is analyzed in the limit of strong magnetic fields when the transport is mediated by the electron-hole states bound to the sample edges and NS interface, i.e., in the Integer Quantum Hall Effect regime.The Andreev-type process of the conversion of the quasiparticle current into the superflow is shown to be strongly affected by the mixing of the edge states localized at the NS and insulating boundaries. The magnetoconductance in 2D NS structures is calculated for both quadratic and Dirac-like normal state spectra. Assuming a random scattering of the edge modes we analyze both the average value and fluctuations of conductance for an arbitrary number of conducting channels.