Combined structure-factor phase measurement and theoretical calculations for mapping of chemical bonds in GaN

B. Jiang, J. M. Zuo, D. Holec, C. J. Humphreys, M. Spackman, John Spence

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

For non-centrosymmetric crystals, the refinement of charge-density maps requires highly accurate measurements of structure-factor phase, which can now be obtained using the extinction-free convergent-beam electron microdiffraction method. We report here accurate low-order structure-factor phases and amplitudes for gallium nitride (GaN) in the wurtzite structure. The measurement accuracy is up to 0.1% for amplitude and 0.2° for phases. By combining these with high-order structure factors from electronic structure calculation, charge-density maps were obtained. Fine bonding features suggest that the Ga-N bonds are polar and covalent, with charge transfer from Ga to N; however, the polarity effect is extremely small.

Original languageEnglish (US)
Pages (from-to)446-450
Number of pages5
JournalActa Crystallographica Section A: Foundations of Crystallography
Volume66
Issue number4
DOIs
StatePublished - Jul 2 2010

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Keywords

  • charge density
  • convergent beam diffraction
  • gallium nitride
  • phase problem
  • poloar bonds
  • tric crystals

ASJC Scopus subject areas

  • Structural Biology

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