Single Atom Spectroscopy
M. Varela2, A. R. Lupini2, H. M Chrwisten2, A. Y. Borisevich2, S. J. Pennycook2, N. Dellby3, O. J. Krivanek3, P. D. Nellist3, S. D. Findlay4, M. P. Oxley4, L. J. Allen4
Physical Review Letters, 92, 095502 (2004)
Full Article (PDF 872 KB)
The ability to detect, identify and perform spectroscopic studies of individual atoms in their active environment within materials or on their surfaces would unravel unsolved mysteries in catalysis, structural materials, electronic materials and nanoscience. Researchers at Oak Ridge National Laboratory have shown how electron energy loss spectroscopy in a scanning transmission electron microscope can now achieve single atom sensitivity. Spectra below locate and identify a single Lanthanum (La) atom inside a crystal of calcium titanate. A strong La M4/5 ionization signal is detected when the beam is passed down one particular calcium column, and the atom depth can be deduced by comparison with simulations.