Spin filtration in a single-stranded antiferromagnetic helix with slowly varying disorder: Higher order electron hopping

TL;DR

This paper demonstrates that in a helical antiferromagnetic system, slowly varying disorder combined with higher-order electron hopping can achieve near-perfect spin filtration without external electric fields, offering new spintronic device possibilities.

Contribution

It reveals that disorder alone, enhanced by higher-order hopping, can produce high spin filtration in antiferromagnetic helices, a novel approach compared to prior electric field methods.

Findings

Disorder induces high spin filtration at low bias and high temperature.

Higher-order hopping creates non-uniform energy levels aiding spin selectivity.

Spin filtration can reach up to 100% in the studied system.

Abstract

This work explores spin filtration in a helical magnetic system within a tight-binding framework, where neighboring magnetic moments are aligned antiparallel. The helix experiences a slowly-varying diagonal disorder, following a cosine form, which creates a finite energy mismatch between up and down spin channels. Unlike earlier studies that relied on external electric fields, this investigation demonstrates that disorder alone can achieve high spin filtration, even at low bias and high temperatures. Higher-order electron hopping in the helix leads to a non-uniform energy level distribution, facilitating favorable spin filtration, sometimes reaching $100\%$. The interplay between higher-order hopping and atypical disorder may enable selective spin transmission through various antiferromagnetic helices, potentially opening new avenues for functional elements.