Single Atom Spectroscopy in Low-Dimensional Materials using Low-voltage STEM

In this presentation, single atom spectroscopy by means of EELS and EDX will be demonstrated to discriminate individual atoms in low-dimensional materials. It has remained a challenge for scientists to see and identify individual atoms since Dalton first proposed distinct atoms in his atomic theory It is emphasized here that information on the bonding/electronic states has become accessible for single atoms through the EELS fine-structure analysis as well as the spin state. Such analysis was not possible until recently because of an intrinsic limitation, namely, the inevitable irradiation damage due to the huge number of electrons required to realize a high enough signal-to-noise ratio for fine-structure analysis from a single atom.