Andreev interferometer with three superconducting electrodes

TL;DR

This paper presents a theoretical analysis of a three-electrode Andreev interferometer, revealing how interface resistance and conductance ratios affect current sensitivity and modulation, with potential for optimizing device performance.

Contribution

It develops a quasiclassical theory for three-electrode Andreev interferometers, exploring effects of interface resistance and conductance on current modulation and sensitivity.

Findings

Significant current sensitivity at subgap voltages with high interface resistance.

Multiple Andreev reflection enhances current modulation when conductances are comparable.

Diverse features identified for optimizing interferometer performance.

Abstract

We develop a quasiclassical theory of Andreev interferometers with three superconducting electrodes. Provided tunneling interface resistance between one superconducting electrode and the normal metal strongly exceeds two others, significant current sensitivity to the external magnetic flux is observed only at subgap voltages. If all barrier conductances are comparable, multiple Andreev reflection comes into play and substantial current modulation can be achieved in both subgap and overgap voltage regimes. Our analysis reveals a large variety of interesting features which can be used for performance optimization of Andreev interferometers.