Dynamic observation and motion tracking of individual gold atoms with HAADF-STEM imaging

A modern aberration-corrected scanning transmission electron microscope (STEM) is used to study the motion of individual gold atoms on an amorphous carbon film. With a probe size of 0.7 Å, individual gold atoms are clearly resolved. Sequential Z-contrast images are captured with ten frames per second, and moving atoms are tracked frame-by-frame with the feature point tracking algorithm. The tracked trajectories give direct visualization of individual atoms' movements, and the number of tracked atoms in each frame is quantified. The result indicates that the observed behaviors of atoms are mainly dominated by the beam-induced motion.