Surface structures formed by individual adsorption and coadsorption of Mn and Bi on Cu(001), studied by LEED

We have studied the individual adsorption of Mn and Bi, and their coadsorption on Cu(0 0 1) by low-energy electron diffraction (LEED). For Mn, we have determined the c(2 x 2) structure formed at 300 K, whose structure had been determined by several methods. We reconfirmed by a tensor LEED analysis that it is a substitutional structure and that a previously reported large corrugation (0.30 angstrom) between substitutional Mn and remaining surface Cu atoms coincides perfectly with the present value. In the individual adsorption of Bi, we have found a c(4 x 2) structure, which is formed by cooling below similar to 250 K a surface prepared by Bi deposition of similar to 0.25 ML coverage at 300 K where streaky half-order LEED spots appear. The c(4 x 2) structure has been determined by the tensor LEED analysis at 130 K and it is a substitutional structure. In the coadsorption, we found a c(6 x 4) structure, which has been determined by the tensor LEED analysis. It is very similar to the previously determined structure of the c(6 x 4) formed by coadsorption of Mg and Bi, and embedded MnBi4 clusters are arranged in the top Cu layer instead of MgBi4. Large lateral displacements of Bi atoms in the c(6 x 4)-(Mn + Bi) suggest that the Mn atoms undergo the size-enhancement caused by their large magnetic moment. (c) 2005 Elsevier B.V. All rights reserved.