Avoidance of ghost atoms in holographic low-energy electron diffraction (LEED)

It is pointed out that real-space images recovered from LEED I/E data by th e current holographic reconstruction algorithm can contain strong artifacts which can be misinterpreted as atomic images ('ghost atoms'), thereby misg uiding a subsequent structural refinement through conventional LEED. We sho w that such ghost atoms can be avoided by using an alternative approximatio n to the kernel in the reconstruction integral. This is demonstrated for bo th calculated and experimental intensities of the structure considered, i.e . a (2 x 2) phase of 6H-SiC(000 (1) over bar). A theory is also developed f or a practical implementation of a more general kernel which fully takes ac count of the scattering of an electron by the substrate atoms before its fi rst encounter with the adatom (beam splitter).