Deconstruction of theAu{110}−(1×2)surface

Abstract

The deconstruction of the $\mathrm{Au}{110}\ensuremath{-}(1\ifmmode\times\else\texttimes\fi{}2)$ 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 ${\mathrm{Ar}}^{+}$ sputtering. The sharp, anisotropic features observed in the images from the ordered $(1\ifmmode\times\else\texttimes\fi{}2)$ 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 $(1\ifmmode\times\else\texttimes\fi{}2)$ MR structure are still observed even near 700 K where three-dimensional roughening begins. These $(1\ifmmode\times\else\texttimes\fi{}2)$ 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 $(1\ifmmode\times\else\texttimes\fi{}1)$ structure. The results accentuate the remarkable stability of the $(1\ifmmode\times\else\texttimes\fi{}2)$ 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.