Fig. 4: Gradient DNA moiré superlattice.
From: DNA moiré superlattices
a,b, A schematic of seed S(G) for gradient DNA moiré superlattices in square lattice bilayers. Z3 has a trapezoid-shaped cross-section with two non-parallel growth surfaces, which induce a gradual change in lattice orientation and, thus, in moiré periodicity pM. c, Simulation and class-average TEM image of seed S(G). The growth surfaces are marked in the TEM image. Scale bar, 20 nm. d–f, Structural characterizations of the seeded second layer on Z3 of seed S(G). d, TEM image analysed by marking the SST units, each comprising 4-helix × 4-helix (white boxes). The arrows highlight the change in lattice orientation. The solid arrows indicate a gradual clockwise change, while the dashed arrow indicates a sharp counterclockwise change. Red and blue lines indicate surface a2nd and surface b2nd, respectively. Scale bar, 20 nm. e,f, FFT patterns for the overall (e) and selected (f) areas. g–i, Structural characterizations of the gradient DNA moiré superlattice. g, A TEM image with boxes highlighting the gradual changing moiré superunits. Scale bar, 20 nm. h, A heat map of the moiré superunits with arrows indicating the direction from smaller to larger pM. The solid arrows indicate a gradual clockwise change, while the dashed arrow indicates a sharp counterclockwise change. Scale bar, 20 nm. i, FFT patterns for the selected areas with white lines corresponding to the first layer and coloured lines corresponding to the second layer. The respective twist angles are shown on top.
