Direct Observation of Covalency between O and Disordered Pb in Cubic PbZrO₃

Abstract

In cubic PbZrO 3 , which undergoes an antiferroelectric phase transition, the distinct disorder of Pb at twelve sites toward the neighboring O is detected for the first time by analyzing high-energy X-ray powder diffraction data. In the charge density distributions, the covalent nature of the Pb–O bond is also revealed, which proves the existence of electron hybridization between O and disordered Pb in cubic PbZrO 3 . None of these structural characteristics of PbZrO 3 were found in the previously studied cubic PbTiO 3 structure [Y. Kuroiwa et al. : Phys. Rev. Lett. 87 (2001) 217601], which undergoes a ferroelectric phase transition. This may be a clue to understanding why PbTiO 3 and PbZrO 3 respectively show ferroelectric and antiferroelectric phase transitions.