What is it about?

Motivated by recent high resolution results on the inversion domain boundaries (IDB) in gallium nitride, we refine by ab initio DFT calculations the well established atomic model IDB∗ derived by Northrup et al. This allows us to recover these experimental results obtained by coherent x-ray diffraction and showing small additional shifts of the polarity domains, in particular, 8 pm shift along the hexagonal direction. The influence of boundary conditions and electrostatic fields (IDB-IDB and IDB-surface interactions) on the results and the existence of metastable solutions is carefully discussed to stress the accuracy of the method. These results demonstrate a cross-talk between advanced characterization tools and state-of-the-art ab initio calculations that opens perspectives for the structural analysis of defects in the picometer range.

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Why is it important?

- Improvement of IDB model for gallium nitride - Explain experimental results obtained by coherent X-ray diffraction. - Cross-talk between experiments and ab initio calculations - Picometer shift obtained by these state-of-the-art calculations.


- Link with optical spectroscopy - Study other types of defects - Study the influence of ionicity/covalence on the shift

Dr Joel Eymery
Commissariat Energie Atomique (CEA)

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This page is a summary of: Towards simulation at picometer-scale resolution: Revisiting inversion domain boundaries in GaN, October 2018, American Physical Society (APS), DOI: 10.1103/physrevb.98.165306.
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