Regensburg 2004 – scientific programme

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O: Oberflächenphysik

O 14: Postersitzung (Adsorption an Oberflächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Phasenübergänge, Rastersondentechniken, Struktur und Dynamik reiner Oberflächen)

O 14.19: Poster

Monday, March 8, 2004, 18:00–21:00, Bereich C

Influence of adsorbed rare gas on the Au(111) surface state: combined UPS and STS studies — •T. Andreev, I. Barke, and H. Hövel — Universität Dortmund, Experimentelle Physik I, D-44221 Dortmund

The Au(111) Shockley surface state is compared before and after adsorbing different rare gas layers (Ar, Kr and Xe). We used ultraviolet photoelectron spectroscopy (UPS) and scanning tunneling spectroscopy (STS) in combination to get comprehensive information by using the advantages of both methods. The energetic position of the surface state in UPS is determined using an analytic model, which takes the finite angular resolution of the electron energy analyzer into account. STS was measured for pure Au(111) as well as for the surface covered with a monolayer Kr and Xe and it is analyzed with an extended Kronig-Penney model for the 23 × √3 reconstruction. The first rare gas monolayer induces energetic shifts of 50 to 150 meV increasing with the gas atomic number, whereas a second monolayer results only in small additional shifts of 3 to 18 meV. Using an image potential model it is possible to characterize these shifts qualitatively. For a semiquantitative analysis we use the phase accumulation model.