Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Poster Session III (Solid/liquid interfaces; Metals; Semiconductors; Oxides and insulators)

O 58.14: Poster

Mittwoch, 28. März 2012, 18:15–21:45, Poster B

Adsorption geometry and phase diagram of Br/Pd(110) — •Alexander Menzel, Peter Amann, Michael Cordin, and Erminald Bertel — Institute for Physical Chemistry, University of Innsbruck, Austria

As the adsorbate system Br/Pt(110)-c(2x2) at 0.5ML Bromine coverage can be used as a low-dimensional model system [1], we were interested in the phase diagram of Br and Cl on the isoelectronic Pd(110) surface.

The electronic surface resonances, which are responsible for the low-dimensional behavior in the case of Pt(110), can be found in ARPES spectra at Pd(110), too. The phase diagram of Br- and Cl-covered Pd(110) was studied for coverages below 1ML. Using LEED, well ordered c(2x4) and c(4x2) Br/Pd(110) phases were found for a coverage of 0.25ML and 0.75ML, respectively. A continuous spot splitting of fractional order spots is observed for coverages in between. As shown by STM, the spot splitting below 0.5ML is due to anti-phase domains in [001]-direction, whereas above 0.5ML, the splitting is caused by continuous compression along [110]-direction. Interestingly, the c(2x2) phase expected for 0.5ML cannot be observed in the temperature range of the experiments (above 100K). A diagram of the observed phases is presented.

[1] P. Amann et al., Eur. Phys. J B 10, 15 (2010).