Structure analysis of two-dimensional Holmium silicide by low energy electron diffraction

The Ho/Si(111)-1 x 1 and H-Ho/Si(111)-1 x 1 surfaces have been investigated by low energy electron diffraction I-V curve analysis. Several structural models have been tried and the optimum structure has been obtained using a combination of search methods. In the case of the Ho/Si(111) surface, Ho at oms sit on T4 sites of the Si(111) near bulk-like layer and are located und erneath a Si bilayer which is rotated 180 degrees with respect to the subst rate Si layers. This is the same structure as proposed by medium-energy ion scattering. In the case of the H-Ho/Si(111)-1 x 1 surface, Si atoms in the surface bilayer have normal stacking and are located above the same latera l position as the topmost bulk layer. (C) 2001 Elsevier Science B.V. All ri ghts reserved.