[Zurück]

M. Setvin, M. Reticcioli, Z. Wang, Z. Jakub, M. Schmid, C. Franchini, U. Diebold:
"The polar KTaO₃ (001) surface: Electronic structure and CO adsorption";
Poster: DPG-Frühjahrstagung (DPG Spring Meeting) of the Surface Science Division, SurfaceScience21, virtual; 02.03.2021.

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.