Properties of Cu films on Pt(1Â 1Â 1) revealed by AES, LEED, and DEPES

The experimental and theoretical results presented in this work concern the growth mechanism and structural investigations of the ultrathin copper layers on Pt(1 1 1) at the adsorption temperatures from 330 K to 450 K. The growth mode of Cu on Pt(1 1 1) and the crystalline structures up to the first four adsorbate monolayers (4 ML) were studied by using Auger electron spectroscopy, low-energy electron diffraction, and (in the case of 1 ML) directional elastic peak electron spectroscopy. At 330 K Cu forms a misfit adsorbate layer with a supercell of Cu(13 × 13) on Pt(12 × 12). The formation of the misfit Cu overlayer characterized by the LEED pattern continues to about 4 ML. At higher coverages the diffraction pattern characteristic of the Cu(1 1 1) surface was observed. At 450 K the pseudomorphic growth of 1 ML of adsorbate was noted. The experimental DEPES anisotropy maps compared with the theoretical data obtained by using the multiple scattering formalism confirms the misfit structure of the Cu layer at 330 K and pseudomorphic overlayer with threefold hollow adsorption sites of type A at 450 K.