Negative Magnetoresistance in Andreev Interferometers

TL;DR

This paper investigates the conductance behavior of a diffusive Andreev interferometer, revealing a strong phase-dependent modulation and a reversed resistance trend, supported by both theoretical calculations and experimental data.

Contribution

It presents the first combined theoretical and experimental study of phase-dependent conductance modulation in a cross-shaped Andreev interferometer, including the prediction of reversed resistance behavior.

Findings

Conductance strongly modulates with superconducting phase.

Reversed resistance versus phase difference predicted.

Quantitative agreement achieved with experimental data when considering diamagnetic screening.

Abstract

We consider transport in a diffusive cross-shaped Andreev interferometer geometry, both theoretically and experimentally. A strong and unexpected modulation of the conductance with the superconducting phase is found. In particular, a reversed resistance vs. phase difference is predicted, where the resistance is decreased by a phase gradient. A comparison of our quasiclassical calculation with experimental data shows quantitative agreement if we account for diamagnetic screening.