Quantitative Analysis of Individual Atoms in the Channels of Beryl

Aberration-corrected scanning transmission electron microscopy (STEM) allows the imaging of single atoms in bulk crystals, usually with high angle annular dark field (HAADF) images [1], but in special cases also with STEM spectroscopy methods [2]. However, the detection of single atoms in a bulk crystal is challenging and depends on various experimental parameters such as specimen thickness, crystal orientation, composition of the matrix and the type of dopants. For substitutional dopants, the channeling of the electron waves in the crystal must be considered, whereas for single atoms on interstitial sites such as in porous materials, other difficulties such as the electron probe confinement arise [3].