Non-local current correlations in ferromagnet/superconductor nanojunctions

TL;DR

This paper investigates non-local current correlations in ferromagnet/superconductor nanojunctions, demonstrating how inserting a diffusive region enhances and modulates the non-local current over distance.

Contribution

It introduces a new nanojunction structure that significantly amplifies non-local currents and analyzes their behavior in diffusive regimes.

Findings

Non-local current can be increased by inserting a diffusive region.

The non-local current exhibits a maximum at a certain separation.

Decay of non-local current follows a power law with distance.

Abstract

When two fully polarized ferromagnetic (F) wires with opposite polarizations make contact with a spin-singlet superconductor, a potential-induced current in wire 1 induces a non-local current of equal magnitude and sign in wire 2. The magnitude of this current has been studied in the tunneling limit and found to decay exponentially with the distance between the contact. In this paper we propose a new structure in which this novel non-local effect is increased by orders of magnitude. We study the spin-dependent electronic transport of a diffusive nanojunction and demonstrate that when a normal diffusive region is placed between the F leads and superconductor, the non-local initially increases with the separation between the F leads, achieving a maximum and decays as a power law with increasing separation.