Index
Astigmatism 2- and 3-fold

Astigmatism 2-fold or 3-fold is introduced by selecting its amplitude and angle to the first (h,k,l) direction of the reciprocal basis (1,0,0) on the figure below. Interactive stigmatism adjustment is available in the HREM map Plot panel of the Bloch-wave calculation, the HREM map and the super-cell imager of the multislice calculation (use the Plot option checkbox and Image radio button of the Iteration tab). Astigmatism induces mainly 2-fold (Fig. 1) or 3-fold (Fig. 2) distortions of the atomic columns.

Figure1a

Figure 1a GaAs [1,0,0] with 2-fold astigmatism.

Figure1b

Figure 1b 2-fold astigmatism settings.

Figure2a

Figure 2a GaAs [1,0,0] with 3-fold astigmatism.

Figure2b

Figure 2b 3-fold astigmatism settings.