Offsets and polarization at strained AlN/GaN polar interfaces

TL;DR

This paper uses first-principles calculations to analyze how strain affects band offsets, interface dipoles, and polarization at strained AlN/GaN polar interfaces, revealing a significant asymmetry influenced by lattice mismatch.

Contribution

It provides the first detailed computational study of strain effects on band offsets, interface dipoles, and polarization asymmetry at AlN/GaN interfaces.

Findings

Large forward-backward asymmetry in band offsets.

Strain-induced piezoelectric fields significantly affect interface properties.

Relaxed geometric structures influence formation energies.

Abstract

The strain induced by lattice mismatch at the interface is responsible for the different value of the band discontinuities observed recently for the AlN/GaN (AlN on GaN) and the GaN/AlN (GaN on AlN) polar (0001) interface. We present a first-principles calculation of valence band offsets, interface dipoles, strain-induced piezoelectric fields, relaxed geometric structure, and formation energies. Our results confirm the existence of a large forward-backward asymmetry for this interface.