Intrinsic 1D moiré superlattice in large-angle twisted bilayer WTe₂

Moiré effects in two-dimensional (2D) twisted van der Waals structures are attracting great interests and recent studies also revealed their potential as platforms to study one-dimensional (1D)-like physical phenomena. However, the moiré superlattices themselves cannot be purely 1D as long as the twist angle is limited to small values, because the long-range periodicities along multiple direction exit simultaneously. In this study, we focus on twisted bilayer tungsten ditelluride (t-WTe₂) with large twist angles, and realized pure 1D moiré superlattices with twist angles around 62° and 58°. The moiré patterns of t-WTe₂ were directly investigated using transmission electron microscope (TEM), and the diffraction patterns exhibited a unique pairing feature indicating the formation of pure 1D moiré superlattice in the sense that the long-range periodicity exists only along one direction. We further theoretically revealed the intrinsic origin of the formation of large-angle moiré superlattices and the appearance of pure 1D moiré patterns. Our concept can be easily adopted to other 2D materials, being a general platform to study moiré effects and dimensionality of twisted structures with large twist angles.