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Alpha-Gallium(010) surface reconstruction: a LEED structural analysis of the (1x1) room temperature and (2rt2xrt2)R45 degrees low temperature structures

  • Author(s): More, S.
  • Soares, E.A.
  • Hove, M.A. Van
  • Lizzit, S.
  • Baraldi, A.
  • Grutter, Ch.
  • Bilgram, J.H.
  • et al.
Abstract

The geometric structure of the alpha-Ga(010)-(1x1) room temperature structure and its (2rt2xrt2) R45 degrees reconstruction below 232 K have been determined using Low Energy Electron Diffraction (LEED) structure analysis. The room temperature structure conforms to the cut-dimer model, forming a two-dimensional metallic structure with only minimal lateral displacements of the atoms. The topmost interlayer distance is 1.53 Angstrom, corresponding to a spacing expansion of 2% from the bulk. In the low-temperature structure, the surface atoms shift to dimerize within the top two layers, resulting in a network of mostly covalent bonds, which form both parallel and perpendicular to the surface plane. The bond lengths of some of these dimers are about 10% shorter than the bond length found in the alpha-Ga bulk and are thus shorter than any Ga-Ga bonds reported so far.

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