Nature 366, 143–146 (1993)

In this Letter, we reported that it was possible to undertake chemical analysis with atomic resolution in a scanning transmission electron microscope—a capability that has subsequently been demonstrated in a variety of other contexts. We now realize that, in the course of revising the manuscript in response to reviewers' comments, errors were introduced into the paper, resulting in inconsistencies in the manner in which key data were presented. In particular, the electron energy-loss spectroscopy (EELS) data central to the work (Fig. 3b) were not subject to the background subtraction processes as described in the paper, despite assurances to the contrary that we offered at the time to both the referees and the Nature editors. Rather, we have now concluded that only spectra 5-7 were processed in the manner described; for spectra 1-4, owing to an error, the data were reproduced from ref. 7, where a standard exponential background subtraction was used. The exponential background subtraction method is widely used in the field and is an entirely acceptable method of analysis, and therefore this error in no way affects the key scientific claim of the paper, namely that it is possible to perform atomic-resolution chemical analysis in the scanning transmission electron microscope. We sincerely regret this error and any confusion that may have resulted.