Dr Michele A Conroy
Department of Materials, ICL
Abstract: Dynamic charged ferroelectric domain walls overturn the classical idea that our electronic circuits need to consist of fixed components of hardware. With their own unique electronic properties and exotic functional behaviours all confined to their nanoscale width, DWs represent a completely new 2D material phase. The most exciting aspect of domain walls is that they can be easily created, destroyed and moved simply by an applied stimulus. The dynamic nature of conducting domain walls gives them the edge over other novel systems and may lead to them being the next promising disruptive quantum technology. This is an area of research at its very early stages with endless possible applications. However, to harness their true potential there is a great deal of the fundamental physics yet to uncover. As the region of interest is atomically thin and dynamic, it is essential for the physical characterisation to be at this scale spatially and time-resolved.
The results of this presentation will show how the applied electric field of a scanning transmission electron microscopy (STEM) probe is a viable in situ technique, providing a new platform for understanding the fundamentals physics of topologically protected quantum state dynamics. As the applied electric field of an electron probe can be controlled in terms of dose, probe size, direction and speed, a diverse set of experiments is possible without complicated sample preparation. I will also show how higher order topologies such as charged vertices can be formed when the scanning direction of the STEM probe is controlled. The new insights presented here required the resolution allowed by aberration corrected STEM due to the 2D nature of the domain walls, reinforcing the idea that advancements in STEM techniques are essential for the progress of quantum information sciences.