Coexistence of Ferro- and Antiferroelectric Behavior

Ferroelectric domain walls are a rich source of emergent electronic properties and unusual polar order. For example, recent studies showed that the polarization configuration of ferroelectric walls can go well beyond the conventional Ising-type structure, exhibiting Néel-, Bloch-, and vortex-like polar patterns.<br/><br/>In my talk, I will present novel types of anti-polar domain walls and discuss their structure and unusual physical properties. In the first part of my talk, I will show that charged domain walls arise in K₃[Nb₃O₆(BO₃)₂]. The domain wall bound charges arise from a finite canted moment associated with the material’s antiferroelectric-like order, leading to distinct local piezoelectric and electrostatic responses. In the second part, I will talk about the emergence of anti-polar order at domain walls in Pb₅Ge₃O₁₁. The domain walls are highly mobile and exhibit an energetically costly antiparallel ordering of dipoles along the longitudinal direction, which we attribute to the hyperferroelectric nature of the system. The results provide new insight into the complex polar textures of domain walls, expanding previous studies towards anti-ferroic phenomena.