Figure 3. The superball shape changes the densely packed RC stacking sequence.

(a) For each of the superball shapes the structural angle, β, and ratio of the lattice spacing and the superball edge-to-edge length, d/L, were determined. The error bars of the latter represent the scaled standard deviation in superball size, σ_L/L. Good agreement is found with the theoretical β (black dotted line) expected for a close-packed (d/L=1, blue dashed line) rhombic crystal (RC) planes. (b,c) Schematic illustrations of the position of successive close-packed RC planes that can be either positioned into (b) the hollow-site (HRC) or (c) the bridge-site (BRC) position and the resulting 3D structure for both stacking sequences. (d) Numerically calculated 2D patterns of P(q) and S(q) for a superball shell with m=3.6 and shell thickness to length ratio, t/L=0.03. Due to constructive and destructive interference between the RC planes, only specific hkl peaks are allowed in the S(q) pattern for each of the two stacking sequences, resulting in a hexagonal pattern for HRC or a rhombic pattern for BRC, that are enhanced by P(q).