Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 44: Focus Session: Surfaces and Interfaces of (Incipient) Ferroelectrics (joint session O/KFM)
O 44.7: Talk
Wednesday, September 7, 2022, 17:15–17:30, H3
The polar KTaO3 (001) surface: Electronic structure and CO adsorption — Zhichang Wang1, Michele Reticcioli2, Zdenek Jakub1, Michael Schmid1, Gareth Parkinson1, Ulrike Diebold1, Cesare Franchini2, and •Martin Setvin3 — 1TU Wien, Vienna, Austria — 2University of Vienna, Vienna, Austria — 3Charles University, Prague, Czech Republic
Polar surfaces offer intriguing physical and chemical properties applicable in electronics or catalysis. Cleaving the KTaO3 perovskite along its polar (001) plane provides a well-defined, bulk-terminated surface with KO and TaO2 terminations [1]. As-cleaved surfaces exhibit a high concentration of in-gap states; these electrons predominantly reside at the TaO2-terminated parts of the surface. These electrons can affect surface chemistry, as is demonstrated for CO molecules. CO has two adsorption configurations on the TaO2 termination, and the CO differs in how it couples to the excess electrons. DFT calculations indicate that CO preferentially couples to electron bipolarons.
The work was supported by FWF project P32148-N36, by GACR 20-21727X and GAUK Primus/20/SCI/009.
[1] M. Setvin, M. Reticcioli, F. Poelzleitner et al., Science 359, 572 (2018)