Unraveling the Jahn-Teller effect in Mn doped GaN using the Heyd-Scuseria-Ernzerhof hybrid functional

TL;DR

This study uses advanced hybrid functional calculations to investigate the Jahn-Teller effect in Mn-doped GaN, revealing an insulating ground state and a transition in hole localization from GaN to GaAs, aligning with experimental data.

Contribution

It demonstrates the importance of hybrid functionals in accurately capturing Jahn-Teller distortions and electronic states in Mn-doped GaN, providing new insights into the material's properties.

Findings

Mn in GaN exhibits an insulating ground state due to Jahn-Teller distortion.

Hybrid functional calculations agree with experimental observations.

A transition from localized to delocalized Mn hole states occurs from GaN to GaAs.

Abstract

We present an ab-initio study of the Mn substitution for Ga in GaN using the Heyd-Scuseria-Ernzerhof hybrid functional (HSE). Contrary to semi-local functionals, the majority Mn t$_{2}$ manifold splits into an occupied doublet and an unoccupied singlet well above the Fermi-level resulting in an insulating groundstate, which is further stabilized by a sizeable Jahn-Teller distortion. The predictions are confirmed using $GW$ calculations and are in agreement with experiment. A transition from a localized to a delocalized Mn hole state is predicted from GaN to GaAs.