Symmetry and the Role of the Anion Sublattice in Aurivillius Oxyfluoride Bi₂TiO₄F₂

Abstract

The photocatalytic and dielectric behaviors of Aurivillius oxyfluorides such as Bi₂TiO₄F₂ depend sensitively on their crystal structure and symmetry but these are not fully understood. Our experimental work combined with symmetry analysis demonstrates the factors that influence anion order and how this might be tuned to break inversion symmetry. We explore an experimental approach to explore anion order, which combines Rietveld analysis with strain analysis.