A search for ferromagnetism in transition-metal-doped piezoelectric ZnO

TL;DR

This computational study investigates the potential for ferromagnetism in transition-metal-doped ZnO, finding that additional hole doping is necessary to achieve ferromagnetic ground states, which are also compatible with piezoelectricity.

Contribution

The paper demonstrates that transition-metal doping alone does not induce ferromagnetism in ZnO; additional hole doping is required, proposing a practical p-type doping scheme.

Findings

Robust ferromagnetism is not achieved by Co or Mn substitution alone.

Additional hole doping is necessary for ferromagnetism in ZnO.

A practical scheme for p-type doping in ZnO is proposed.

Abstract

We present the results of a computational study of ZnO in the presence of Co and Mn substitutional impurities. The goal of our work is to identify potential ferromagnetic ground states within the (Zn,Co)O or (Zn,Mn)O material systems that are also good candidates for piezoelectricity. We find that, in contrast to previous results, robust ferromagnetism is not obtained by substitution of Co or Mn on the Zn site, unless additional carriers (holes) are also incorporated. We propose a practical scheme for achieving such $p$-type doping in ZnO.