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Publications in Scientific Journals:

P. Amann, M. Cordin, C. Braun, A. Lechner, A. Menzel, E. Bertel, C. Franchini, R. Zucca, J. Redinger, N. Baranov, S. Diehl:
"Electronically driven phase transitions in a quasi-one-dimensional adsorbate system";
European Physical Journal B, 75 (2010), 15 - 22.



English abstract:
A quasi-1D system is prepared using the Pt(110) surface as a template. The electronic surface
resonance structure is studied by angle-resolved photoemission spectroscopy for the clean surface as well
as for different Bromine coverages. A Fermi surface mapping reveals saddle points at the Fermi level in the
interior of the surface Brillouin zone. Correspondingly, a maximum in the static response function χ(q, 0)
at the connecting vector q is expected. With 1/2Gx < q < 2/3Gx one observes indeed a 3-fold periodicity
around defects and a 2-fold periodicity at low temperature for ΘBr = 0.5 ML. Cooling of a defect-free
c(2 2)−Br/Pt(110) preparation counter-intuitively results in a loss of long-range order. Motivated by
DFT calculations this is attributed to an anomalous order-order phase transition into the (2 1) phase
accompanied by intense, strongly anisotropic fluctuations within a temperature range of ∼200 K. The
peculiar behaviour is rationalised in terms of a competition between inter-adsorbate repulsion and an
adsorbate triggered 2kF interaction in the substrate.

Created from the Publication Database of the Vienna University of Technology.