Domains and Domain Walls in Ferroelectrics

by Lucas M. Eng (Dresden University of Technology)

Thursday 5 Sept 2024, 11:00 → 13:00 UTC

For the last 15 years, domain walls (DWs) in ferroelectrics have become very attractive as nanoscale elements, that allow to bottom-up assemble novel devices and functionalities. DWs constitute boundaries, i.e. surfaces and interfaces, eventually crossing the full (single) crystalline material, break the crystal symmetry, and hence significantly modify the materials dynamics, giving rise to states localized near or even within these extended defects. The recent development of nanotechnology stimulated experimental methods dedicated to characterizing these localized states.

The lecture will focus on domains and domain walls in ferroelectric materials. I will start at the fundamentals of ferroelectrics, explaining their phase transitions and the surprising properties of domain walls. One key aspect will focus on domain wall conductivity in single crystals such as BaTiO3 and LiNbO3, which will be shown to be reconfigurable 2-dimensional electron gases (2DEGs) at room temperature. I will also introduce into a manifold of methods for visualizing and analyzing these DWs, and how to quantify their impact on temperature and mechanical stress.