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J. Redinger:
"Structure determination of doping-induced surface phase transitions in the Br/Pt(110) system";
Vortrag: Seminar Institut für Allgemeine Physik (IAP), TU Wien; 07.01.2003.

The formation of a charge density wave (CDW) phase in the quasi one-dimensional system Br/Pt(110) has been reported recently. Here we present a detailed investigation of the transitions in the Br/Pt(110) adsorption system, focusing on the atomic structure of the phases c(2x2), p(3x1), and p(4x1) as determined by quantitative low-energy electron diffraction (LEED) and density functional theory (DFT) calculations. Whilst in the parent c(2x2) phase with coverage Q = 1/2 ML the Br atoms occupy every second short-bridge site on the unreconstructed p(1x1) Pt(110) surface, the adatoms in the p(3x1) phase, with ideal coverage Q = 2/3 ML reside in every third short-bridge and long-bridge site, respectively.
For 1/2 < Q < 0.58 ML LEED intensity and STM measurements reveal the nucleation of p(3x1) islands surrounded by areas with a local coverage of 1/2 ML. For these areas STM measurements hint towards dynamical fluctuations of the Br positions at room temperature.
Increasing the coverage up to Q = 3/4 ML, a p(4x1) phase is formed with the adatoms found in every fourth short-bridge and in two long-bridge sites in between.