SKM 2021 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 1: Focus Session I: Ferroics - Domains and Domain Walls

KFM 1.2: Talk

Tuesday, September 28, 2021, 10:30–10:45, H2

Charged ferroelectric domain walls for a.c. signal control — •Jan Schultheiss¹, Erik Lysne¹, Lukas Puntigam², Zewu Yan^3,4, Edith Bourret⁴, Stephan Krohns², and Dennis Meier¹ — ¹NTNU Norwegian University of Science and Technology, 7034, Trondheim, Norway — ²University of Augsburg, 86159, Augsburg, Germany — ³ETH Zurich, 8093, Zurich, Switzerland — ⁴Lawrence Berkeley National Laboratory, 94720, Berkeley, CA, USA

Ferroelectric domain walls are natural interfaces separating volumes with different orientation of the spontaneous polarization. Depending on the local charge state, the domain walls exhibit unusual direct current (d.c.) conduction ranging from insulating to metallic-like behavior. Because of their unique electronic properties, they bear great potential as nanoelectronic components, serving, e.g., as switches and synaptic devices. In contrast to the functional d.c. behavior at charged walls, their response to alternating currents (a.c.) falls into an uncharted territory. Here, we explore the a.c. characteristics of charged ferroelectric walls in ErMnO₃ in the adiabatic regime (kHz-MHz), using a combination of atomic force microscopy and macroscopic dielectric spectroscopy. We demonstrate a pronounced non-linear response at the electrode-domain wall junction, which correlates with the charge state of the wall. The dependence on the a.c. drive voltage and frequency enables us to reversibly switch between uni- and bipolar output signal, providing conceptually new opportunities for the application of charged domain walls as functional nano-elements in a.c. circuitry.