Published in

IOP Publishing, Journal of Physics: Condensed Matter, 12(20), p. 122201, 2008

DOI: 10.1088/0953-8984/20/12/122201

Links

Tools

Export citation

Search in Google Scholar

Polar multipoles in wurtzite-like crystals (ZnO, GaN)

Journal article published in 2008 by Stephen W. Lovesey ORCID, Ewald Balcar
This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

Full text: Unavailable

Green circle
Preprint: archiving allowed
Orange circle
Postprint: archiving restricted
Red circle
Published version: archiving forbidden
Data provided by SHERPA/RoMEO

Abstract

A theoretical analysis and simulation of resonance-enhanced x-ray Bragg diffraction by wurtzite-like crystals is presented for parity-even and polar (parity-odd) atomic resonant processes. Compounds with this crystal structure are of great interest for a range of technologies. The electronic properties of a crystal are represented as ground-state expectation values of atomic multipoles, and the analysis respects all selection rules imposed on diffraction by atomic and crystal symmetry. Our main focus is directed at weak, space-group forbidden reflections that are a result of angular anisotropy in the cation electron distribution. Expected variations of the diffracted intensity with orientation of the crystal due to angular anisotropy of the electron distribution are simulated. The crystal symmetry allows the intensity to be coupled to circular polarization in the primary beam and illustrative examples for the creation of circular polarization in diffraction are provided. These polarization effects are unique probes of electronic structure. Moreover, we prove that recent diffraction experiments on ZnO reveal the pyroelectric (dipole) and polar octupole moment of the cation.