The atomic geometry of the Al͑100͒-c(2ϫ2)-Li phase formed by adsorption of 1 2 -ML Li on Al͑100͒ at room temperature has been determined by analysis of extensive low energy electron-diffraction ͑LEED͒ measurements. The structure is found to be a binary surface alloy, in which Li atoms occupy fourfold-coordinated substitutional sites formed by displacing every second Al atom in the first layer of the substrate. The surface structure is very similar to the ͑100͒ plane of the metastable, bulk Al 3 Li alloy. An analysis of experimental LEED data for clean Al͑100͒ leads to the conclusions that the first interlayer spacing is expanded by about 2% with respect to the bulk value, and that the vibrations of Al atoms in the first layer are about twice as large as for atoms in the bulk. Adsorption of Li leads to a contraction of nearly 6% of the first Al-Al interlayer spacing, and further enhances the vibrations of Al atoms in the first, mixed Al/Li layer ͓S0163-1829͑99͒16331-8͔

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The heteroepitaxial growth of TiN on MgO(001), deposited by reactive magnetron sputtering, has been studied in situ. Using real-time specular x-ray reflectivity, layer-by-layer growth was observed, with the surface roughening decreasing with an increase in the deposition temperature. Higher temperatures also resulted in lower growth rates. The film thickness was measured with specular x-ray reflectivity. Using off-plane Bragg–Brentano as well as grazing incidence in-plane wide angle scattering, the pseudomorphic growth of TiN to the underlying MgO(001) was established. Transmission electron microscopy reveals atomic planes passing through the MgO–TiN boundary, thus confirming heteroepitaxial growth.

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