Extended Data Fig. 2: DF TEM domain boundary contrast image obtained by DF TEM analysis.

a–c, DF TEM images obtained from the second-order Bragg peaks. \(g=\bar{1}2\bar{1}0\), \(g=11\bar{2}0\) and \(g=2\bar{1}\bar{1}0\) Bragg peaks are used to obtain the DF images shown in a, b and c, respectively. d, Schematic illustrating the displacement vectors Δ_i (i = 1, 2, 3) associated with the domain boundaries. The displacement vectors Δ_i are drawn on top of the atomic structure to denote the directions and magnitudes of the displacements. e, Composite-colour DF TEM image obtained from the three sets of DF images shown in Extended Data Fig. 2a–c by summing them after colour contrasting the individual images. As a result, the coloured lines indicate the domain walls with the characteristic displacement vectors shown in d. f,g, Distinct domain boundary networks formed at the adjacent interfaces. Domain boundary network formed at the bottom interface (f) and at the top interface (g) are drawn as coloured dashed lines. When the bottom interface is twisted with finite angle (θ₂₃ ≠ 0°), a triangular domain-wall network appears as a result of the lattice reconstruction as in f. When the top interface exhibits the twist angle θ₁₂ = 0°, a parallel array of domain walls appears. The insets in f and g represent the schematic drawings for kagome-like domain lattices, in which black and white regions represent the rhombohedral stacking orders and the grey regions indicate the Bernal stacking orders. The domain walls are visualized with distinct coloured lines, corresponding to the displacement vectors shown in d with the same colours. In the twisted interface (f), the directions of each domain wall are mostly parallel with the displacement vector, indicating that all of the domain walls can be characterized with the shear type of displacements. In the untwisted interface (g), one type of domain wall (marked by the red lines in g) exhibits the displacement vector that has a non-zero orthogonal component to the domain-wall direction, revealing that the uniaxial displacement is incorporated along such domain walls.