Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 66: Oxide Surfaces 2
O 66.6: Vortrag
Donnerstag, 8. September 2022, 12:00–12:15, S053
Transformation from honeycomb binary oxide to quasicrystalline ternary oxide — •Loi V. Tran, Stefan Förster, and Wolf Widdra — Institute of Physics, Martin-Luther-University Halle-Wittenberg, Halle, Germany
Oxide quasicrystals (OQCs) are examples of aperiodically-ordered 2D materials. They have been found for 2D layers derived from BaTiO3 on Pt(111) [1]. Their dodecagonal structure results from Ba decoration of a TinOn network where n = 4 (decorated with no Ba atom), 7 (decorated with one Ba atom) and 10 (decorated with two Ba and two addional O atoms). In contrast, periodic Ti2O3 honeycomb structures with Ti6O6 rings are well known in literature [2,3]. Here, we report on the transition of such honeycomb Ti2O3 structures to dodecagonal OQCs by adsorption of Ba and subsequent annealing. The structural transition is monitored with LEED and workfunction measurements. Upon room temperature Ba deposition, Ti2O3 honeycomb structure remains and Ti6O6 rings are decorated with Ba, reducing the workfunction from 5.12 to 2.97 eV. Annealing to 873 K in oxygen converts the honeycomb structure into a dodecagonal OQC, for which the workfunction increases to 3.85 eV. The workfunction changes associated with the transformation will be discussed in context of the height differences of Ba ions above the surface and the resulting dipole strength.