Electronic structure and Jahn-Teller effect in GaN:Mn and ZnS:Cr

TL;DR

This paper investigates the Jahn-Teller effect in Mn-doped GaN and Cr-doped ZnS semiconductors using ab-initio and analytical methods, emphasizing the importance of electron correlation and distortion effects for accurate electronic structure modeling.

Contribution

It demonstrates that combining Jahn-Teller distortion with strong electron correlation is essential for correct electronic structure prediction in these DMS materials.

Findings

Jahn-Teller energy gain aligns with experimental data

Strong electron correlation is crucial for insulating states

Ab-initio and ligand field theory results are consistent

Abstract

We present an ab-initio and analytical study of the Jahn-Teller effect in two diluted magnetic semiconductors (DMS) with d4 impurities, namely Mn-doped GaN and Cr-doped ZnS. We show that only the combined treatment of Jahn-Teller distortion and strong electron correlation in the 3d shell may lead to the correct insulating electronic structure. Using the LSDA+U approach we obtain the Jahn-Teller energy gain in reasonable agreement with the available experimental data. The ab-initio results are completed by a more phenomenological ligand field theory.