Deconstruction of the Au{110}-(1x2) surface

The deconstruction of the Au{110}-(1 x 2) missing-row (MR) surface has been studied by variable temperature scattering and recoiling imaging spectrometry (SARIS). SARIS images were acquired over the range of 298-720 K and for an amorphousized surface produced by high-dose Ar+ sputtering. The sharp, anisotropic features observed in the images from the ordered (1 x 2) surface at 298 K change monotonically with increasing temperature into broadened, more featureless images in which the first-layer blocking arcs shift to very low exit angle values. The basic features of the (1 x 2) MR structure are still observed even near 700 K where three-dimensional roughening begins. These (1 x 2) features are completely obliterated on the sputtered amorphousized surface, depicting a surface that is dominated by three-dimensional roughening. Classical ion trajectory simulations using the scattering and recoiling imaging code are used to probe the effects of vibrational amplitude and conversion to a (1 x 1) structure. The results accentuate the remarkable stability of the (1 x 2) MR structure up to the roughening temperature and exclude early proposals of an order-disorder transition via lattice gas formation. The findings are in agreement with more recent models in which roughening induces a simultaneous deconstruction transition. [S0163-1829(98)06939-2].