Regensburg 2000 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
O: Oberflächenphysik
O 9: Adsorption an Oberflächen (II)
O 9.4: Vortrag
Montag, 27. März 2000, 17:00–17:15, H37
Adsorption of Xe atoms on metal surfaces: surprising results and understanding – a DFT study — •Juarez L.F. da Silva1, Catherine Stampfl2, and Matthias Scheffler1 — 1Fritz-Haber-Institut, Berlin — 2Northwestern University, Evanston
About ten years ago it was argued (based on He atom scattering data) that Xe on Pt(111) prefers atop adsorption sites: a quite surprizing, widely not accepted, and certainly not understood suggestion. Later, a spin-polarized LEED study of Xe (√3×√3)R30∘ at Pt(111) “showed” that Xe adsorbs preferentially in hollow sites. A recent LEED analysis, however, indicated that Xe in the (√3×√3)R30∘ structure on Cu(111), Pt(111), and Pd(111) assumes the on-top position [1].
To determine what is indeed the most stable site for Xe on the three mentioned surfaces, and to find out why Xe does what it does, we performed density functional theory calculations using the local-density and also the generalized gradient approximation, employing the full-potential linear augmented plane wave method. We mapped out the total-energy surfaces (in particular at the top, bridge, fcc and hcp hollow sites) and find that Xe atoms prefer to adsorb atop. While this is in qualitative agreement with the LEED study [1], certain important structural aspects of the LEED analysis are questioned. We analyzed the Xe induced workfunction change as well as the local Xe polarization and explain the results in a simple physical picture.
[1] Th. Seyller, M. Caragiu, R. D. Diehl, P. Kaukasoina, and M. Lindroos, Phys. Rev. B 60, 11084 (1999); and references therein.