Reduced Hamiltonian for Electronic States of Dilute Nitride Semiconductors

TL;DR

This paper introduces a new reduced Hamiltonian model based on perturbation theory and group theory to accurately describe the conduction band and band gap bowing in dilute nitride semiconductors like GaN_xAs_{1-x}.

Contribution

It provides a novel, simplified Hamiltonian that captures the band gap behavior in GaNAs, clarifying the origin of band gap bowing through intervalley mixing.

Findings

The model accurately predicts band gap shrinkage.

Intervalley mixing explains the band gap bowing.

The reduced Hamiltonian simplifies previous complex models.

Abstract

We present a novel model to describe conduction band of GaN_xAs_{1-x} (GaNAs). As well known, GaNAs shows exotic behavior such as large band gap bowing. Although there are various models to describe the conduction band of GaNAs, origin of the band gap bowing is still under debate. On the basis of perturbation theory, we show that the behavior of conduction band is mainly arising from intervalley mixing between Gamma and L or X. By using renormalization technique and group theoretical treatment, we derive a reduced Hamiltonian which describes well the band gap shrinkage of GaNAs.