From classical to quantum spintronics: Theory of coherent spin injection and spin valve phenomena

TL;DR

This paper develops a quantum transport theory for ferromagnetic heterojunctions, revealing a quantum spin valve effect driven by coherence that differs fundamentally from classical spintronics, impacting device design and experimental analysis.

Contribution

It introduces a novel quantum coherence-based model predicting a spin valve effect without net spin current, advancing understanding of quantum spin transport in heterostructures.

Findings

Quantum coherence induces a spin valve effect without net spin current.

Quantum interference alters the relationship between spin and charge transport.

Implications for designing quantum coherent spintronic devices.

Abstract

We present a theory of coherent quantum transport in ferromagnetic/ non-magnetic/ ferromagnetic heterojunctions. We predict quantum coherence to give rise to a quantum spin valve effect that, unlike its familiar classical analog, occurs even in the absence of a net spin current through the heterostructure. Thus the relationship between spin and charge transport is qualitatively different in the presence of quantum interference than in the (semi)classical regime. This has important implications for the design of quantum coherent spintronic devices and the interpretation of experiments.