Minimum detectable solute concentration in atomic-resolution transmission electron microscopy

The minimum solute concentration necessary to produce an observable change in image contrast in atomic-resolution transmission electron microscopy was investigated by multislice image-simulation techniques. The results show that local changes in specimen composition produce regular changes in image contrast, and that the minimum detectable solute concentration for any system of matrix and solute can be predicted from a simple formula based on a rule of mixtures, using only the atomic numbers of the matrix and solute elements. Optimum specimen and microscope conditions for observing local changes in specimen composition and the possibility of using atomic-resolution transmission electron microscopy for absolute determination of specimen composition are also discussed.