Figure 5. For CaFe₂As₂, aberration corrected HAADF images viewed normal to [0 0 1], and atomic displacements plotted as distances between As and Fe along x, or |x_As-x_Fe| averaged in the y direction in (a) p1, (b) p2, and (c) p3 crystalline samples.

Strain in p1 is relieved by atomic displacements of Fe atoms upon annealing. In p3, Ca/As atoms remain in their original positions, whereas in p2, these atoms are also displaced in every second layer.