Density functional theory study of La2Ce2O7: Disordered fluorite versus pyrochlore structure

D. E. P. Vanpoucke*, P. Bultinck, S. Cottenier, V. Van Speybroeck, I. Van Driessche

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

The crystal structure of lanthanum cerium oxide (La2Ce2O7) is investigated using ab initio density functional theory calculations. The relative stability of fluorite- and pyrochlorelike structures is studied through comparison of their formation energies. These formation energies show the pyrochlore structure to be favored over the fluorite structure, apparently contradicting the conclusions based on experimental neutron and x-ray diffraction (XRD). By calculating and comparing XRD spectra for a set of differently ordered and random structures, we show that the pyrochlore structure is consistent with diffraction experiments. For these reasons, we suggest the pyrochlore structure as the ground-state crystal structure for La2Ce2O7.

Original languageEnglish
Article number054110
Number of pages9
JournalPhysical Review B (Condensed Matter and Materials Physics)
Volume84
Issue number5
DOIs
Publication statusPublished - 12 Aug 2011
Externally publishedYes

Keywords

  • LANTHANUM-CERIUM OXIDE
  • AUGMENTED-WAVE METHOD
  • SOL-GEL ROUTES
  • ELECTRONIC-STRUCTURE
  • MOLECULAR-DYNAMICS
  • CRYSTAL-STRUCTURE
  • PHASE
  • APPROXIMATION
  • CONDUCTIVITY
  • LATTICE

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