Contrast Reversal in Atomic-Resolution Chemical Mapping
P Wang, AJ D'Alfonso, SD Findlay, LJ Allen, AL Bleloch
PHYSICAL REVIEW LETTERS | AMER PHYSICAL SOC | Published : 2008
We report an unexpected result obtained using chemical mapping on the new, aberration corrected Nion UltraSTEM at Daresbury. Using different energy windows above the L2,3 edge in 011 silicon to map the position of the atomic columns we find a contrast reversal which produces an apparent and misleading translation of the silicon columns. Using simulations of the imaging process, we explain the intricate physical mechanisms leading to this effect.
W. and A. L. B. acknowledge financial support from the EPSRC for the SuperSTEM project. L.J.A. acknowledges support from the Australian Research Council. S. D. F. received support from the Japanese Society for the Promotion of Science.