Lawrence Berkeley National Laboratory

Nowadays material science benefits from high-resolution transmission electron microscopy (HRTEM) with a resolution that extents to the information limit of field emission microscopes that can reach into the sub Angstrom region. The procedure involves a reconstruction of the electron exit wave from a focal series of images or imaging with a Cs corrected microscope. We utilized a CM200FEG instrument equipped with a Cs corrector [1] toinvestigate quantitatively the core structure of an obtuse dislocation reaction in gold. A determination of the structure from a single lattice image is compared with the result from an exit wave reconstruction. Quantitative information is obtained by extraction of the column positions surrounding the dislocation core with precision on a pm level. Moreover, it is shown that the large scattering power of the gold atoms (atomic number z = 79) can be utilized to extract the number of gold atoms in individual atomic columns from reconstructed electron exit-waves of wedge shaped samples. A comparison of multi-slice calculations with experiments gives guidelines on how resolution affects the limit as to which the number of atoms in a particular column can be determined from a phase change of the electron exit wave.