Surface magnetization in non-doped ZnO nanostructures

TL;DR

This study uses ab initio calculations to explore how extended defects like surfaces and grain boundaries, rather than point defects, induce ferromagnetism in non-doped ZnO nanostructures, highlighting the role of delocalized, spin-polarized states.

Contribution

It demonstrates that extended defects, not intrinsic point defects, are responsible for ferromagnetism in non-doped ZnO nanostructures, providing new insights into magnetic mechanisms.

Findings

Ferromagnetism is mediated by extended defects such as surfaces and grain boundaries.

Delocalized, spin-polarized states are responsible for long-range magnetic interactions.

Intrinsic point defects are not the primary cause of ferromagnetism in these nanostructures.

Abstract

We have investigated the magnetic properties of non-doped ZnO nanostructures by using {\it ab initio} total energy calculations. Contrary to many proposals that ferromagnetism in non-doped semiconductors should be induced by intrinsic point defects, we show that ferromagnetism in nanostructured materials should be mediated by extended defects such as surfaces and grain boundaries. This kind of defects create delocalized, spin polarized states that should be able to warrant long-range magnetic interactions.