Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 36: Surfaces and Films: Forces, Structure and Manipulation
O 36.8: Vortrag
Dienstag, 26. Februar 2008, 16:00–16:15, MA 041
Investigating surface dynamics with inelastic X-ray scattering — •Bridget Murphy1, Martin Müller1, Jochim Stettner1, Herwig Requardt2, Jorge Serrano2, Michael Krisch2, and Werner Press1 — 1Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany — 2ESRF, BP 220, F-38043 Grenoble Cedex 9, France
Inelastic x-ray scattering in grazing incidence conditions provides a new tool to selectively study either surface or bulk lattice dynamics in a single experiment. It is possible to study acoustic and optical surface phonon modes currently with a 3meV resolution over a wide range of momentum space and make a direct comparison between surface and bulk dispersion. In particular 2H−NbSe2 and 2H−TaSe2will be discussed. For these materials a Kohn anomaly has been previously reported. Our data demonstrate that the softening of the Kohn anomaly at the 2H−NbSe2 surface is significantly greater that that reported for the bulk [1]. This is an indication of a relaxation in the top most layers of the crystal. Temperature dependent studies will be presented.
[1] B. M. Murphy, H. Requardt, J. Stettner, J. Serrano, M. Krisch, M. Müller, W. Press, Phys. Rev. Lett. 95, 256104 (2005)