Emergence of half-metallicity in suspended NiO chains

TL;DR

This study shows that while bulk NiO is antiferromagnetic and insulating, short suspended NiO chains can become half-metallic conductors with high magnetoresistance, useful for spintronic applications.

Contribution

It demonstrates the emergence of half-metallicity in short suspended NiO chains, contrasting with the insulating bulk form, through ab initio electronic structure and transport calculations.

Findings

Infinite NiO chains are insulating.

Short suspended NiO chains are half-metallic.

Chains exhibit large magnetoresistance and spin-valve behavior.

Abstract

Contrary to the antiferromagnetic and insulating character of bulk NiO, one-dimensional chains of this material can become half-metallic due to the lower coordination of their atoms. Here we present ab initio electronic structure and quantum transport calculations of ideal infinitely long NiO chains and of more realistic short ones suspended between Ni electrodes. While infinite chains are insulating, short suspended chains are half-metallic minority-spin conductors which display very large magnetoresistance and a spin-valve behaviour controlled by a single atom.