• Selbach, Sverre
• Smabraten, Didrik
• Conroy, Michele
• Bangert, Ursel
• Aschauer, Ulrich
• Ramasse, Quentin M.
• Moore, Kalani
• Shapovalov, Konstantin
• Hunnestad, Kasper
• Gruverman, Alexei
• Meier, Dennis
• Gregg, Marty
• Stengel, Massimiliano
• Orphus, Colin

Abstract

Ferroelectric domain walls are a rich source of emergent electronic properties and unusual polar order. Recent studies showed that the configuration of ferroelectric walls can go well beyond the conventional Ising-type structure. Néel-, Bloch-, and vortex-like polar patterns have been observed, displaying strong similarities with the spin textures at magnetic domain walls. Here, we report the discovery of antiferroelectric domain walls in the uniaxial ferroelectric Pb5Ge3O11. We resolve highly mobile domain walls with an alternating displacement of Pb atoms, resulting in a cyclic 180º flip of dipole direction within the wall. Density functional theory calculations show that Pb5Ge3O11 is hyperferroelectric, allowing the system to overcome the depolarization fields that usually suppress antiparallel ordering of dipoles along the longitudinal direction. Interestingly, the antiferroelectric walls observed under the electron beam are energetically more costly than basic head-to-head or tail-to-tail walls. The results suggest a new type of excited domain-wall state, expanding previous studies on ferroelectric domain walls into the realm of antiferroic phenomena.

Topics

• density
• impedance spectroscopy
• theory
• texture
• density functional theory
• magnetic domain wall