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

Abstract

It is pointed out that real-space images recovered from LEED I /Edata by the current holographic reconstruction algorithm can containstrong artifacts which can be misinterpreted as atomic images(`ghost atoms'), thereby misguiding a subsequent structuralrefinement through conventional LEED. We show that such ghost atomscan be avoided by using an alternative approximation to the kernelin the reconstruction integral. This is demonstrated for bothcalculated and experimental intensities of the structure considered,i.e. a (2×2) phase of 6H-SiC(0001̄). A theory is alsodeveloped for a practical implementation of a more general kernelwhich fully takes account of the scattering of an electron by thesubstrate atoms before its first encounter with the adatom(beam splitter).