Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 57: Surface dynamics II

O 57.7: Vortrag

Mittwoch, 24. März 2010, 16:30–16:45, H40

Vibrational Spectroscopy of Copper on Cu(111) — •Olaf Skibbe, Heiner Maslosz, Jan Pischel, Diana Vogel, and Annemarie Pucci — Kirchhoff-Institut für Physik, Im Neuenheimer Feld 227, D-69120 Heideberg

It is known from literature that on some stepped copper surfaces vibrations exist at energies significantly above that of the bulk phonon band [1]. By use of high-resolution electron energy loss spectroscopy (HREELS) we found for sub-monolayer amounts of copper evaporated to the cooled Cu(111) surface vibrations at even higher energies (50% above the highest bulk phonon energy). It could be shown that the vibration is polarized perpendicularly to the surface. The vibrational energy shifts slightly upon annealing, and the peak disappears at temperatures above 200 K. Additional measurements of the work function change upon annealing have been performed.

In addition, to clarify data analysis, we examine the interaction of typical molecules from the residual gas (such as CO and O₂) with the roughened surface.

Since it is known that roughened surfaces provide a higher chemical activity than pristine single crystal surfaces, we hope to gain deeper insight in the interaction of molecules with defect-rich surfaces via the observation of the extra-ordinary high energy vibrational mode.

[1] A. Kara, P. Staikov, T.S. Rahman, J. Radnik, R. Biagi, and H.-J. Ernst. Phys. Rev. B 61(8):5714-5718, 2000.