Illustration: Lawrence Berkeley National Laboratory
Formation of self-interstitials in germanium, imaged with the TEAM 0.5 aberration-corrected transmission electron microscope by Alloyeau et al. . (Left) High-resolution micrograph of the germanium  surface showing location of occupied tetragonal interstitial site (arrow). (Right) 3D representation of the interstitial atom position in a germanium crystal along the  direction. The blue shapes indicate the interstitial positions, with the elongation being the noise-limited precision of the measurement.