Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 55: Oxide and insulator surfaces: Structure, epitaxy and growth II

O 55.1: Vortrag

Mittwoch, 11. März 2026, 10:30–10:45, HSZ/0204

Modulated structures in complex 2D oxides — •Muriel Wegner, Loi V. Tran, Oliver Krahn, Stefan Förster, and Wolf Widdra — Martin-Luther-Universität Halle-Wittenberg, Germany

Crystalline materials are typically characterized by a set of lattice vectors that reflect the materials dimensionality. In surface science we are used to two vectors spanning the lattice. However, systematic lattice modifications, which can be displacive in nature or connected to a different periodicity in a given materials property like magnetism, can call for the need of additional modulation vectors for a proper interpretation of the diffraction pattern. Such modulated structures are rarely discussed in surface science. Here we present the structure of a Ba-Ti-O monolayer film grown on Pd(111) and Pt(111). On Pd(111) this structure is commensurate and fully determined by two lattice vectors. In contrast, on Pt(111) four vectors are needed, two describing the average structure and two additional modulation vectors. This Ba-Ti-O structure is a complex network of Ti-O rings, in which 53% of the rings are decorated with Ba atoms. On Pd(111) it forms a rhombic structure with a periodicity of 23.2 Å and an inner angle of 129.7^∘. On Pt(111) it grows with the identical lattice parameters. However as a consequence of the modified substrate spacing, the domain size is restricted by systematic inclusions of defects, which cause a modulation period of about 100 Å.

Keywords: modulation; 2D oxide; STM; LEED; Ba-Ti-O