Hole states in wide band-gap diluted magnetic semiconductors and oxides

TL;DR

This paper explains discrepancies in experimental findings on magnetically doped GaN and ZnO by proposing a generalized alloy theory that accounts for hole-spin interactions, revealing new electronic states and effects.

Contribution

It introduces a generalized alloy theory to explain conflicting experimental results in magnetically doped wide band-gap semiconductors and predicts the formation of a mid-gap Zhang-Rice-like state.

Findings

Strong coupling between valence-band holes and localized spins.

Formation of a mid-gap Zhang-Rice-like state.

Increase of the band-gap with magnetic ion concentration.

Abstract

Puzzling disagreement between photoemission and optical findings in magnetically doped GaN and ZnO is explained within a generalized alloy theory. The obtained results show that the strong coupling between valence-band holes and localized spins gives rise to a mid-gap Zhang-Rice-like state, to a sign reversal of the apparent p-d exchange integral, and to an increase of the band-gap with the magnetic ion concentration.