A comparison of atomistic and continuum theoretical approaches to determine electronic properties of GaN/AlN quantum dots

TL;DR

This paper compares atomistic and continuum models to accurately predict the electronic properties of GaN/AlN quantum dots, revealing strong conduction-valence band coupling and the impact of spin-orbit effects.

Contribution

It provides a detailed comparison of multiband k.p, effective bond-orbital, and tight-binding models for GaN/AlN quantum dots, highlighting the importance of band coupling.

Findings

Good agreement between microscopic models and 8-band k.p

Weak spin-orbit coupling influences wave functions

Strong conduction-valence band coupling in GaN/AlN

Abstract

In this work we present a comparison of multiband k.p-models, the effective bond-orbital approach, and an empirical tight-binding model to calculate the electronic structure for the example of a truncated pyramidal GaN/AlN self-assembled quantum dot with a zincblende structure. For the system under consideration, we find a very good agreement between the results of the microscopic models and the 8-band k.p-formalism, in contrast to a 6+2-band k.p-model, where conduction band and valence band are assumed to be decoupled. This indicates a surprisingly strong coupling between conduction and valence band states for the wide band gap materials GaN and AlN. Special attention is paid to the possible influence of the weak spin-orbit coupling on the localized single-particle wave functions of the investigated structure.