Long-range effect of a Zeeman field on the electric current through the helical metal-superconductor interface in Andreev interferometer

TL;DR

This paper investigates how a Zeeman field influences the electric current in a topological insulator-superconductor interface within an Andreev interferometer, revealing long-range, nonlocal effects due to spin interactions and superconducting coherence.

Contribution

It demonstrates the long-range impact of Zeeman fields on electric current through a helical metal-superconductor interface, highlighting nonlocal effects caused by spin interactions and superconducting proximity.

Findings

Electric current varies with Zeeman field strength and direction.

Interference effects depend on mutual orientations of Zeeman fields.

Long-range coherence effects are due to superconducting proximity.

Abstract

It is shown that the spin-orbit and Zeeman interactions result in phase shifts of Andreev-reflected holes in disordered topological insulator, or normal Rashba spin-orbit-coupled wires, which are in a contact with an s-wave superconductor. Due to interference of the holes reflected through different paths in Andreev interferometer the electric current through the contact varies depending on the strength and direction of the Zeeman field. It also depends on mutual orientations of Zeeman fields in different shoulders of the interferometer. Such a nonlocal effect is a result of the long-range coherency caused by the superconducting proximity effect. This current has been calculated within the semiclassical theory for Green functions of a dirty system.