STRUCTURE OF ULTRATHIN FILMS Ni/Au(001) AND Au/Ni(001): A STUDY USING MOLECULAR-DYNAMICS SIMULATION. O.V.Lysenko (Volf), A.A.Katsnelson, A.E.Moroz, V.S.Stepanyuk, O.S.Trushin.

Growth of the ultrathin films Ni on substrate Au(001) and Au on substrate Ni(001) at room temperature are studied by means of molecular- dynamics simulation using Lennard- Jones potential.

From structural Ni/Au(001) and Au/Ni(001) data can be deduced: The first epilayer Au exhibits fcc Au(111) film. Larger radius of Au atoms (by 16%) in comparison to Ni atoms gives rise to the orientation change of this layer relatively to substrate. If positions of Au atoms correspond to (111) lattice plane than greater number of ordering particles of Au coincides with positions of Ni atoms. The structure of the second epilayer is the same of the first one.

In process of Ni atoms adsorption on substrate Au(001) Ni atoms are placed upon interatomic hollow of substrate topmost layer. Besides, due to smaller radius of Ni atoms, they do not touch each other. Moreover, part of peaks of pair correlation function for the first epilayer is asymmetrical. The atomic positions in the next layers are characterized by lots of defects, but basic lattice plane type is the same of topmost layer of substrate. In this case interatomic distances Ni-Ni are smaller than ones in substrate Au-Au by 3-4% (but not by 16%) as in case Au/Ni(001). The weak diffusion of Ni atoms into substrate Au is observed.