Growth of Co layers on Cu(111) studied by forward-focusing angle-resolved x-ray photoemission spectroscopy and real-space imaging

Abstract

We show how the intensity enhancement of angle-resolved x-ray photoelectrons along the emitterscatterer internuclear directions can be used to monitor layer-by-layer growth of Co on Cu(lll). Specifically, we show how the technique can distinguish between fee or hep growth and determine precisely the thickness at which the fee stacking switches to hep. We also show how the interference patterns around each forward-focusing direction can be used to produce real-space images of nearestneighbor atoms in the atomic plane above the emitting atom.

X-RAY PHOTOELECTRON DIFFRACTION STUDY OF A LONG-RANGE-ORDERED ACETATE LAYER ON Ni(110)

“…In general, multiple scattering calculations (MSC) of XPD should be preferred to single scattering simulations since defocussing as well as vibrational effects can be of considerable influence. [40][41][42][43][44][45] However, in a single adsorbed layer scattering along rows of atoms rarely occurs except parallel to the surface, such that defocussing should not be generally important, as indeed some comparisons have shown. 21,38 Vibrational effects, on the other hand, are always important in molecular adlayers, and here MSC should be the first choice.…”

Digital in-line holography for biological applications

“…There is no theoretical reason why submicron resolution should not be attainable by using our method, and we predict this development. Experience with in-line holography, in particular photoelectron and LEED holography, indicates that improved z-axis resolution can be obtained by combining holograms at different wavelengths (29)(30)(31)(32)(33), an option now practical for DIH through the ready availability of cheap green, blue, and UV lasers.…”

Inverse electronic scattering from shifted projections within the Fresnel-Kirchhoff formalism

“…Using the Helmholtz-Kirchhoff integral, 12 inverse scattering was developed by Barton 16 in the context of photoelectron diffraction, by Saldin and de Andres 17 for diffuse lowenergy electron diffraction and Tonner et al 18 for Auger decay, thus leading to atomic reconstructions of the close vicinity of localized sources ͑see also Tong et al, 19 Fadley et al 20 ͒. Following the same ideas, a reconstruction scheme suited to the projection microscope was achieved by Kreuzer et al 8,21 Saldin et al 22 developed an iterative scheme based on a linearized relation between the measured intensities and the atomic densities.…”