Initial growth of Mg films on Ru(0001): An efficient approximation scheme for the LEED analysis of incommensurate structures

The epitaxial growth of incommensurate Mg layers on a Ru(0001) surface is investigated in the coverage range from submonolayers to 3 ML by analyzing low-energy electron-diffraction LEED I(V) data. For the analysis of the 2-ML Mg film, we developed an efficient approximation scheme that allows the determination of mean interlayer spacings without employing the full unit cell. The Mg-Ru spacing is found to be 2.32±0.05 Å, regardless of the presence of further Mg layers above. The Mg-Mg layer spacing in the Mg bilayer is 5%, expanded with respect to the value of the bulk material, while this layer spacing is expanded by only 2.5% after completion of the third Mg layer. The ABAB... stacking sequence is established from the beginning of the film growth. © 1996 The American Physical Society.