Far-Infrared dielectric anisotropy and phonon modes in spontaneously CuPt-ordered (formula presented)

T. Hofmann, V. Gottschalch, M. Schubert

Research output: Contribution to journalArticle

Abstract

The phonon properties of partially (formula presented)-ordered (formula presented) with degrees of ordering (formula presented)(formula presented)(formula presented)(formula presented)(formula presented) determined from generalized ellipsometry measurement of the near-band-gap order birefringence, are studied by far-infrared spectroscopic ellipsometry. We determine precise spectra of the anisotropic dielectric functions. With increasing (formula presented) all (formula presented) phonon modes split in E- and (formula presented)-type vibrations with polarization perpendicular and parallel to the sublattice ordering direction, respectively, and the mode frequencies shift continuously. We demonstrate here that the alloy-induced modes previously observed in highly disordered (formula presented) [Phys. Rev. B 64, 155206 (2001)] have their origin in the ordered atomic arrangement of alike group-III atoms. We propose far-infrared dielectric anisotropy as a sensitive measure for sublattice ordering in multinary III-V alloys.

Original languageEnglish (US)
Pages (from-to)1-10
Number of pages10
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume66
Issue number19
DOIs
StatePublished - 2002

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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