Crossed Andreev effects in two-dimensional quantum Hall systems

TL;DR

This paper demonstrates that in two-dimensional quantum Hall systems, high magnetic fields induce exclusive crossed Andreev reflection, enabling efficient Cooper-pair splitting that is robust against disorder and parameter variations.

Contribution

It reveals that high magnetic fields in 2D quantum Hall systems can produce exclusive crossed Andreev reflection, a novel effect with potential for quantum information applications.

Findings

Exclusive crossed Andreev reflection is achieved in high magnetic fields.

The effect is robust against disorder and parameter changes.

High-efficiency Cooper-pair splitting is realized within the superconductor gap.

Abstract

We study the crossed Andreev effects in two-dimensional conductor/superconductor hybrid systems under a perpendicular magnetic field. Both a graphene/superconductor hybrid system and an electron gas/superconductor one are considered. It is shown that an exclusive crossed Andreev reflection, with other Andreev reflections being completely suppressed, is obtained in a high magnetic field because of the chiral edge states in the quantum Hall regime. Importantly, the exclusive crossed Andreev reflection not only holds for a wide range of system parameters, e.g., the size of system, the width of central superconductor, and the quality of coupling between the graphene and the superconductor, but also is very robust against disorder. When the applied bias is within the superconductor gap, a robust Cooper-pair splitting process with high-efficiency can be realized in this system.