Atomic displacements in the charge ice pyrochlore Bi2Ti 2O6O′ studied by neutron total scattering

Daniel P. Shoemaker, Ram Seshadri, Andrew L. Hector, Anna Llobet, Thomas Proffen, Craig J. Fennie

Research output: Contribution to journalArticlepeer-review


The oxide pyrochlore Bi2Ti2O6O′is known to be associated with large displacements of Bi and O′ atoms from their ideal crystallographic positions. Neutron total scattering, analyzed in both reciprocal and real space, is employed here to understand the nature of these displacements. Rietveld analysis and maximum entropy methods are used to produce an average picture of the structural nonideality. Local structure is modeled via large-box reverse Monte Carlo simulations constrained simultaneously by the Bragg profile and real-space pair distribution function. Direct visualization and statistical analyses of these models show the precise nature of the static Bi and O′ displacements. Correlations between neighboring Bi displacements are analyzed using coordinates from the large-box simulations. The framework of continuous symmetry measures has been applied to distributions of O′ Bi4 tetrahedra to examine deviations from ideality. Bi displacements from ideal positions appear correlated over local length scales. The results are consistent with the idea that these nonmagnetic lone-pair containing pyrochlore compounds can be regarded as highly structurally frustrated systems.

Original languageEnglish (US)
Article number144113
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number14
StatePublished - Apr 15 2010
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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