Towards predictive modelling of near-edge structures in electron energy loss spectra of AlN based ternary alloys

TL;DR

This paper develops a DFT-based method to predict near-edge structures in electron energy loss spectra of AlN-based ternary alloys, enabling better interpretation of experimental spectra through theoretical simulations.

Contribution

It introduces a core hole approach for ternary alloys, extending previous binary-focused methods, and demonstrates good agreement with experimental spectra.

Findings

Predicted spectra match experimental data well.

Core hole charge optimization improves spectral predictions.

Electronic structure analysis explains spectral features.

Abstract

Although electron energy loss near edge structure analysis provides a tool for experimentally probing unoccupied density of states, a detailed comparison with simulations is necessary in order to understand the origin of individual peaks. This paper presents a density functional theory based technique for predicting the N K-edge for ternary (quasi-binary) nitrogen alloys by adopting a core hole approach, a methodology that has been successful for binary nitride compounds. It is demonstrated that using the spectra of binary compounds for optimising the core hole charge ($0.35\,\mathrm{e}$ for cubic Ti$_{1-x}$Al$_x$N and $0.45\,\mathrm{e}$ for wurtzite Al$_x$Ga$_{1-x}$N), the predicted spectra evolutions of the ternary alloys agree well with the experiments. The spectral features are subsequently discussed in terms of the electronic structure and bonding of the alloys.