Consistent set of band parameters for the group-III nitrides AlN, GaN, and InN

TL;DR

This paper derives consistent and accurate band parameters for AlN, GaN, and InN using advanced many-body perturbation theory combined with DFT, providing reliable data for both known and unknown parameters in different crystal phases.

Contribution

It introduces a novel approach combining G0W0 and OEPx-DFT to accurately determine comprehensive band parameters for group-III nitrides.

Findings

Band parameters agree well with experimental data

Provides predictions for previously undetermined parameters

Accurately captures non-parabolic conduction bands

Abstract

We have derived consistent sets of band parameters (band gaps, crystal field-splittings, band gap deformation potentials, effective masses, Luttinger and EP parameters) for AlN, GaN, and InN in the zinc-blende and wurtzite phases employing many-body perturbation theory in the G0W0 approximation. The G0W0 method has been combined with density-functional theory (DFT) calculations in the exact-exchange optimized effective potential approach (OEPx) to overcome the limitations of local-density or gradient-corrected DFT functionals (LDA and GGA). The band structures in the vicinity of the Gamma-point have been used to directly parameterize a 4x4 k.p Hamiltonian to capture non-parabolicities in the conduction bands and the more complex valence-band structure of the wurtzite phases. We demonstrate that the band parameters derived in this fashion are in very good agreement with the available experimental data and provide reliable predictions for all parameters which have not been determined experimentally so far.