Spin-polarized localization in a magnetized chain

TL;DR

This paper explores how spin-polarized states in a magnetic chain can be selectively localized or delocalized, demonstrating robustness of spin filtering against weak disorder, with implications for spintronic device design.

Contribution

It introduces a spin-resolved localization length and reveals a hidden transverse dimensionality enabling spin-selective transport in disordered magnetic chains.

Findings

Spin filtering remains robust under weak disorder.

A new spin-resolved localization length is proposed.

Energy regimes allow selective localization of specific spin states.

Abstract

We investigate a simple tight-binding Hamiltonian to understand the stability of spin-polarized transport of states with an arbitrary spin content in the presence of disorder. The general spin state is made to pass through a linear chain of magnetic atoms, and the localization lengths are computed. Depending on the value of spin, the chain of magnetic atoms unravels a hidden transverse dimensionality that can be exploited to engineer energy regimes where only a selected spin state is allowed to retain large localization lengths. An analysis is carried out to understand the roles played by the spin projections in different energy regimes of the range of states. We introduce a new measure, viz, a spin-resolved localization length for this purpose. We study uncorrelated disorder in the potential profile offered by the magnetic substrate or in the orientations of the magnetic moments concerning a given direction in space. Our results show that the spin filtering effect is robust against weak disorder and hence the proposed systems should be good candidates for experimental realizations of spin-selective transport.