Theory and application of atomic-resolution annular bright-field (ABF) STEM
Abstract: Light elements are of central importance in a wide range of materials and devices. However, direct imaging of light elements at atomic resolution has been an outstanding challenge for the popular and otherwise highly successful technique of scanning transmission electron microscopy. Recently, a new imaging mode, called annular bright field (ABF) imaging, has been found to give direct and robust imaging of both light and heavy elements simultaneously.This new imaging mode is reviewed and compared with other scanning transmission electron microscopy imaging modes.The basic principles of image formation are discussed, with particular emphasis on what makes light elements visible. Example applications, including the direct visualization of hydrogen within a crystalline environment, are presented.
Key words: Scanning transmission electron microscopy, Annular bright-field, Light element imaging