Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 18: Focus Session: Frontiers in Reducible Oxide Surface Science II

O 18.1: Hauptvortrag

Montag, 12. März 2018, 15:00–15:30, HE 101

Surface chemistry of ruthenates — •Ulrike Diebold¹, Daniel Halwidl¹, Wernfried Mayer-Schmözer^{1, 2}, Martin Setvin¹, Florian Mittendorfer^{1, 2}, Josef Redinger^{1, 2}, and Michael Schmid¹ — ¹Institute of Applied Physics, TU Wien, Vienna, Austria — ²Center for Computational Materials Science, TU Wien, Vienna, Austria

Ternary oxides with a perovskite-type crystal structure are of increasing interest in energy-related applications such as solid oxide fuel/electrolysis cells and (photo-) electrocatalysis. Surface science studies can provide an atomic-scale understanding of relevant fundamental processes, but appropriate model systems with a well-defined surface structure are rare. Here we report our results on the cleaved CaO and SrO-terminated surfaces of the Ruddlesden-Popper materials Ca₃Ru₂O₇ and Sr₃Ru₂O₇. Surfaces can easily be prepared by exfoliation in UHV, which provides large, defect-free terraces that are ideal for atomic-scale investigations. We used STM and nc-AFM in combination with XPS and DFT to investigate the adsorption of H₂O [1,2] and O₂. We find that results on the related binary oxides give a good first guide for the adsorption behaviour, and that the tilting and rotation of the materials’ octahedra strongly influence the ordering of overlayers. [1] D. Halwidl, et al. Nature Mater. 15 (2016) 450. [2] D. Halwidl, et al., Nature Comm. 8 (2017) 23.