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 Citations (Scopus)

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 - 2010

Fingerprint

Gallium nitride
Phase measurement
Chemical bonds
gallium nitrides
chemical bonds
Electrons
Charge density
wurtzite
Electronic structure
Charge transfer
Electron beams
polarity
extinction
charge transfer
electron beams
electronic structure
Crystals
crystals
gallium nitride

Keywords

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

ASJC Scopus subject areas

  • Structural Biology

Cite this

Combined structure-factor phase measurement and theoretical calculations for mapping of chemical bonds in GaN. / Jiang, B.; Zuo, J. M.; Holec, D.; Humphreys, C. J.; Spackman, M.; Spence, John.

In: Acta Crystallographica Section A: Foundations of Crystallography, Vol. 66, No. 4, 2010, p. 446-450.

Research output: Contribution to journalArticle

@article{1064dfafa4f8442391c0e38f3c4c927c,
title = "Combined structure-factor phase measurement and theoretical calculations for mapping of chemical bonds in GaN",
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.",
keywords = "charge density, convergent beam diffraction, gallium nitride, phase problem, poloar bonds, tric crystals",
author = "B. Jiang and Zuo, {J. M.} and D. Holec and Humphreys, {C. J.} and M. Spackman and John Spence",
year = "2010",
doi = "10.1107/S0108767310008664",
language = "English (US)",
volume = "66",
pages = "446--450",
journal = "Acta Crystallographica Section A: Foundations and Advances",
issn = "0108-7673",
publisher = "John Wiley and Sons Inc.",
number = "4",

}

TY - JOUR

T1 - Combined structure-factor phase measurement and theoretical calculations for mapping of chemical bonds in GaN

AU - Jiang, B.

AU - Zuo, J. M.

AU - Holec, D.

AU - Humphreys, C. J.

AU - Spackman, M.

AU - Spence, John

PY - 2010

Y1 - 2010

N2 - 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.

AB - 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.

KW - charge density

KW - convergent beam diffraction

KW - gallium nitride

KW - phase problem

KW - poloar bonds

KW - tric crystals

UR - http://www.scopus.com/inward/record.url?scp=77954068200&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77954068200&partnerID=8YFLogxK

U2 - 10.1107/S0108767310008664

DO - 10.1107/S0108767310008664

M3 - Article

C2 - 20555184

AN - SCOPUS:77954068200

VL - 66

SP - 446

EP - 450

JO - Acta Crystallographica Section A: Foundations and Advances

JF - Acta Crystallographica Section A: Foundations and Advances

SN - 0108-7673

IS - 4

ER -