Direct Observation of Ferroelectric Domain Walls in LiNbO3: Wall‐Meanders, Kinks, and Local Electric Charges. (16th September 2016) - Gonnissen, Julie
Abstract : Direct observations of the ferroelectric domain boundaries in LiNbO3 are performed using high‐resolution high‐angle annular dark field scanning transmission electron microscopy imaging, revealing a very narrow width of the domain wall between the 180° domains. The domain walls demonstrate local side‐way meandering, which results in inclinations even when the overall wall orientation follows the ferroelectric polarization. These local meanders contain kinks with "head‐to‐head" and "tail‐to‐tail" dipolar configurations and are therefore locally charged. The charged meanders are confined to a few cation layers along the polarization direction and are separated by longer stretches of straight domain walls. Abstract : The first direct observation of 180° walls in LiNbO3 is reported. The walls are not atomically flat but globally straight when considering a small thickness. Local excess charges populate the walls because these meander and each kink contains a charge. This can be used to construct walls with lots of meanders and hence high carrier densities, allowing novel device fabrications.