Fig. 1: Moiré superlattice of twisted double trilayer graphene (TDTG).

a The lattice structure of the two lowest energy stacking configurations of TDTG when assuming both top and bottom trilayer graphene (TLG) are Bernal stacked. The interfacial atoms are colored to highlight the AB/BA stacking configurations. b The TDTG system after a global slide of the middle layer of one of the TLG sheets. The direction of slide is marked by red arrows indicating the transition from an ABA (dashed red honeycomb lattice) to a BAB configuration. Such a slide, if realized, results in the formation of the unstable BCBACA phase. c, d Mid-IR near-field amplitude (c) and phase (d) of the TDTG stack. Bright (convex) and dark (concave) triangular domains are observed across the sample. Near-field signal in c, d is the 4th harmonic demodulation of the probe tapping frequency (laser illumination at 1000 cm⁻¹, see “Methods” for additional experimental details). Inset of c: Optical image of the TDTG/hBN stack. The bottom and top TLGs are highlighted by purple and green frames, respectively. The red rectangle marks the scan area of (c, d).