A Scale for Atoms

Susanne Stemmer, University of California-Santa Barbara, DMR 0804631

Precisely quantifying the position, type, and number of all atoms in an arbitrarily shaped sample is one of the most sought-after goals of nano-characterization. In this project, we have shown that a truly quantitative approach to atomic resolution scanning transmission electron microscopy (STEM), in which experimental images are directly compared with theory, provides highly accurate (±1 atom), column-by-column counts of atoms in a three-dimensional sample without the need for a calibration standard or any a priori knowledge of sample shape or thickness.

[1] J. M. LeBeau, S. D. Findlay, L. J. Allen, S. Stemmer, Standardless Atom Counting in Scanning Transmission Electron Microscopy, Nano Letters 10, 4405 (2010).

The atomic resolution STEM image shown here is of wedge-shaped gold specimen and contains 10674 atoms and weighs 3.5 (±0.1) attograms. The labels indicate the number of atoms in each column.

Pacific Rim Collaborative Activities

Susanne Stemmer, University of California-Santa Barbara, DMR 0804631

A major component of the program is the international collaborative effort between the theorists, Dr. Findlay at the University of Tokyo (now at Monash University) and Prof. Allen at the University of Melbourne, and the experimentalists at UCSB. Pictured here are former graduate student James LeBeau, the PI at UCSB and the theorists.

The work shown on the previous slide was featured in Science [v. 330 (26 November 2010)].