CONTRAST VARIATION OF AU(111) RECONSTRUCTED SURFACES WITH DEFOCUS IN REM

Reconstruction on a clean Au(111) surface shows complicated contrast in reflection electron microscopic images using many diffracted beams originating from the superstructure. From an analysis of contrast variations with focusing conditions, we deduce that the image consists of phase and amplitude contrast. This contrast is produced by the difference between electron waves scattered from the coincidence and non-coincidence regions on the surface of the Au(111) reconstruction