Single-atom EDX and EELS. (a) HAADF-STEM image of a peapod specimen: a row of single Er atoms in a C82 fullerene cage in a single-wall carbon nanotube. Brighter spots correspond to single Er atoms. 60 keV electrons were used to minimize electron-beam damage in an aberration-corrected Jeol ARM200F. The electron beam was about 1 Å in diameter. (b) EDX spectrum recorded from the yellow line scan in (a). The solid blue arrows show carbon K and erbium M and L lines. The hollow blue arrows show signals due to the grid and the solvent used in specimen preparation. (c) EELS spectrum recorded simultaneously with the EDX spectrum. Adapted from Suenaga et al. (2012).