Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 36: Methods: Atomic and electronic structure

O 36.2: Vortrag

Dienstag, 23. März 2010, 15:15–15:30, H34

Atomic structure of monolayer silica studied by new ion scattering techniques — •Jan Seifert, David Blauth, Andreas Schüller, Stephan Wethekam, and Helmut Winter — Humboldt-Universität zu Berlin, Institut für Physik, Newtonstr. 15, 12489 Berlin, Germany

The structure of ultrathin silica (SiO₂) films grown on a Mo(112) substrate is investigated by three recent experimental techniques using grazing scattering of fast atoms (keV energies) from the film surface: (1) Ion beam triangulation (IBT) where electron emission is recorded for scattering of hydrogen atoms as function of azimuthal orientation of the target. From directions of axial surface channels the position of surface atoms is deduced [1]. (2) Rainbow scattering under axial surface channeling conditions [2]. (3) Fast atom diffraction (FAD). For sufficiently small angles of incidence and projectile energies (2 keV), diffraction patterns can be observed in the angular distribution of scattered atoms and molecules. From the Bragg relation, the periodicity of the interaction potential and from the intensity modulation of the diffraction spots the corrugation of the potential and vertical positions of surface atoms can be determined [3]. Our examples demonstrate the attractive features of grazing fast atom scattering as a powerful tool for structure analysis in surface science.

[1] J. Seifert, D. Blauth, and H. Winter, PRL 103, 017601 (2009)

[2] J. Seifert and H. Winter, Surf. Sci. 603, L109 (2009)

[3] J. Seifert, A. Schüller, H. Winter, R. Włodarczyk, M. Sierka, and J. Sauer, to be published