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arXiv · 1201.2842

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

David Holec·Richard Rachbauer·Daniel Kiener·Peter D. Cherns·Pedro M. F. J. Costa·Clifford McAleese·Paul H. Mayrhofer·Colin J. Humphreys
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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.

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David Holec, Richard Rachbauer, Daniel Kiener, Peter D. Cherns, Pedro M. F. J. Costa, Clifford McAleese, Paul H. Mayrhofer, Colin J. Humphreys. 2012-01-13. Towards predictive modelling of near-edge structures in electron energy loss spectra of AlN based ternary alloys. https://doi.org/10.1103/physrevb.83.165122

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