Oxide materials exhibit a broad range of tunable phenomena, including magnetism, multiferroicity, and superconductivity. Oxide interfaces are particularly intriguing. Their low local symmetry combined with the sensitivity to electrostatics and strain leads to unusual physical properties beyond the bulk properties. Recently, ferroelectric domain walls have attracted attention as a novel type of oxide interface; the walls are spatially mobile and allow controlling electronic signals at the atomic scale, holding great potential as multifunctional 2D systems for future nanoelectronics.
In my talk, I will present unique features that occur at improper ferroelectric domain walls in hexagonal manganites and discuss how these walls can be used to emulate the behavior of key electronic components. For our studies, we choose the p-type semiconductor ErMnO3 as it naturally develops all fundamental types of ferroelectric domain wall at room temperature, including neutral (side-by-side) as well as negatively (tail-to-tail) and positively charged (head-to-head) wall configurations. The walls are explicitly robust and, hence, represent an ideal template onto which the desired electronic behavior can be imposed. I will show how the electronic properties can be optimized and controlled, and discuss the possibility to use such walls for designing 2D digital switches and half-wave rectifiers. Furthermore, I will present an innovative approach that utilizes ionic point defects to wire up domain-wall devices, bringing us one step closer to domain-wall based networks for next-generation nanotechnology.