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C. Deisl, K. Swamy, N. Memmel, E. Bertel, C. Franchini, G. Schneider, J. Redinger, S. Walter, L. Hammer, K. Heinz:
"(3x1)-Br/Pt(110) structure and the charge-density-wave-assisted c(2x2) to (3x1) phase transition";
Physical Review B, 69 (2004), 195405-1 - 195405-13.

After our recent report on the formation of a (3_1) charge-density-wave phase in the quasi-one-dimensional system Br/Pt(110) we present a detailed investigation of the c(2_2) (3_1) transition in the Br/Pt(110) adsorption system. This includes the atomic structure of the (3_1) phase as determined by quantitative low-energy electron diffraction (LEED) and density functional theory calculations. While in the parent c(2_2) phase with coverage = 1/2 ML the Br atoms occupy every second short-bridge site on the unreconstructed (1_1)-Pt(110) surface, the adatoms in the (3_1) phase at coverage = 2/3 ML reside in every third short-bridge and long-bridge sites. Charge densities and vertical relaxations of the Pt atoms forming the short- and long-bridge sites are different, thus yielding a modulation of both, the charge and the position of the outermost Pt atoms with a period of three nearest-neighbor spacings. For 1/2 ML< 0.58 ML LEED intensity and scanning tunneling microscope (STM) measurements reveal the nucleation of (3_1) islands surrounded by areas with a local coverage of 1/2 ML. Within the latter areas the STM measurements indicate dynamical fluctuations of the Br positions at room temperature. In the time average every short-bridge site is sampled by the mobile Br atoms, but in the neighborhood of (3_1) islands every third short-bridge site seems to be preferentially occupied. ©2004 The American Physical Society

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