Observation of Antiferroelectric Domain Walls in a Uniaxial Hyperferroelectric

• Published in: Advanced materials (Weinheim) Vol. 36; no. 39; pp. e2405150 - n/a
• Main Authors: Conroy, Michele, Småbråten, Didrik René, Ophus, Colin, Shapovalov, Konstantin, Ramasse, Quentin M., Hunnestad, Kasper Aas, Selbach, Sverre M., Aschauer, Ulrich, Moore, Kalani, Gregg, J. Marty, Bangert, Ursel, Stengel, Massimiliano, Gruverman, Alexei, Meier, Dennis
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.09.2024; Wiley Blackwell (John Wiley & Sons)
• Subjects: antiferroelectric; Antiferroelectricity; Density functional theory; Depolarization; DFT calculations; Dipoles; domain wall; Domain walls; Electron beams; Ferroelectric domains; Ferroelectric materials; Ising model; Magnetic domains; Magnetic properties; scanning transmission electron microscopy; antiferroelectric; scanning transmission electron microscopy; DFT calculations; domain wall
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202405150

Ferroelectric domain walls are a rich source of emergent electronic properties and unusual polar order. Recent studies show 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, the discovery of antiferroelectric domain walls in the uniaxial ferroelectric Pb5Ge3O11 is reported. Highly mobile domain walls with an alternating displacement of Pb atoms are resolved, resulting in a cyclic 180° 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 the 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. The emergence of antiferroelectric domain walls in ferroelectric Pb5Ge3O11 is reported. Alternating Pb displacements are resolved, resulting in antiferroelectrically coupled dipole layers. Calculations show that Pb5Ge3O11 is hyperferroelectric, allowing the system to stabilize antiparallel ordering of dipoles along the longitudinal direction. The results suggest a new type of excited domain‐wall state, expanding studies on ferroelectric domain walls into the realm of antiferroic phenomena.