Bend conductance of crossed wires in the presence of Andreev scattering

TL;DR

This paper investigates how Andreev scattering influences the bend conductance of mesoscopic crossed wires, predicting a voltage-dependent sign change in conductance in the ballistic regime without magnetic fields.

Contribution

It introduces a theoretical prediction that Andreev scattering can cause a positive bend conductance in mesoscopic crossed wires at small voltages, contrasting with normal device behavior.

Findings

At small voltages, conductance becomes positive due to Andreev scattering.

At large voltages, conductance remains negative.

The effect depends on device size and voltage magnitude.

Abstract

We study the 4-probe bend conductance $G_{14,32}$ of a mesoscopic crossed wire structure in the ballistic regime in the absence of a magnetic field, which for normal devices is usually negative. We predict that for sufficiently large devices and for small applied voltages $G_{14,32}$ becomes positive in the presence of Andreev scattering, but at large voltages $G_{14,32}$ remains negative.