Direct reconstruction of three-dimensional atomic adsorption sites by holographic LEED

We report on the application to measured data of an algorithm for holographic low-energy electron diffraction (LEED), which overcomes the two most important limitations of the technique to date: the open-quote open-quote searchlight close-quote close-quote effect, which tends to highlight only atoms forward scattered by the adsorbates, and the distorting effects on diffuse LEED intensities due to possible long-range order among the adsorbates. The only experimental input required is a set of the most reliably measured diffuse LEED patterns from normally incident electrons. The algorithm is applied to a set of 11 measured diffraction patterns from a K/Ni(001) surface. A fully three-dimensional image is reconstructed from these data by compensating for the anisotropy of the reference wave by an appropriate scattered-wave kernel. copyright 1996 The American Physical Society