Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 6: Oxides and Insulator Surfaces: Structure, Epitaxy and Growth
O 6.3: Vortrag
Montag, 17. März 2025, 11:00–11:15, H8
Ferroelectric perovskite oxides: from bulk to surface polarization — •Dominik Wrana1, Llorenç Albons2, Marta Macyk1, Andrzej Jasicki1, Aji Alexander2, Jesus Redondo2, Igor Sokolovic3, Pavel Kocan2, Konrad Szajna1, Martin Setvin2, and Franciszek Krok1 — 1Institute of Physics, Jagiellonian University, Krakow, Poland — 2Department of Surface and Plasma Science, Charles University, Prague, Czechia — 3Institute of Applied Physics, TU Wien, Vienna, Austria
In leveraging the spontaneous polarization of ferroelectrics for photo-, pyro-, and piezocatalysis, it is essential to develop a comprehensive model of ferroelectricity’s impact on perovskite surfaces.
Here we investigate oxide perovskites, which are known to exhibit record-high efficiencies toward water spitting. Careful analysis of ferroelectricity exhibited on surfaces of single crystals of as-cleaved ferroelectric BaTiO3(001) and KNbO3(001) compared to quantum paraelectric KTaO3(001) reveals phenomena at both single-atom and macroscales. Polarization optical and scanning electron (SEM) microscopy data provides the spatial information of 90∘ ferroelectric domains, which typically have a width of 5-20 µm and length of up to hundreds of um. Actual domain structure and their directionality are provided by piezoresponse force microscopy (PFM) imaging, which also provides the correlation of surface reactivity with polarization.
qPlus ncAFM is used to demonstrate a reversible ferroelectric polarization of (1x1) surfaces at the nanoscale, by application of different tip-sample bias voltages.
Keywords: perovskites; ferroelectricity; oxides; phase transitions; catalysis