MEIS investigations of surface structure

The early work of the FOM-AMOLF group in Amsterdam clearly demonstrated the potential of medium energy ion scattering (MEIS), typically using 100 keV H+ incident ions, to investigate the structure of surfaces, but most current applications of the method are focussed on near-surface compositional studies of non-crystalline films. However, the key strengths of the MEIS technique, notably the use of blocking curves in double-alignment experiments and absolute yield measurements, are extremely effective in providing detailed near-surface structural information for a wide range of crystalline materials. This potential and the underlying methodology, is illustrated through examples of applications to the study of layer-dependent composition and structure in alloy surfaces, in studies of the surface crystallography of an oxide surface (rutile TiO2(1 1 0)) and in investigations of complex adsorbate-induced reconstruction of metal surfaces, including the pseudo-(1 0 0) reconstruction of Cu(1 1 1) induced by adsorption of atomic N and molecular methylthiolate (CH3S-). In addition to the use of calibrated blocking curves, the use of the detailed spectral shape of the surface peak in the scattered ion energy spectra, as a means of providing single-atomic layer resolution of the surface structure, is also discussed.