Macroscopic uniform 2D moiré superlattices with controllable angles

Abstract

Moiré superlattices, engineered through precise stacking of van der Waals (vdW) layers, hold immense promise for exploring strongly correlated and topological phenomena. However, these applications have been held back by the common preparation method: tear-and-stack of Scotch tape exfoliated monolayers. It has low efficiency and reproducibility, along with challenges of twist angle inhomogeneity, interfacial contamination, micrometer sizes, and a tendency to untwist at elevated temperatures. Here we report an effective strategy to construct highly consistent vdW moiré structures with high production throughput, near-unity yield, pristine interfaces, precisely controlled twist angles, and macroscopic scale (up to centimeters) with enhanced thermal stability. We further demonstrate the versatility across various vdW materials including transition metal dichalcogenides, graphene, and hBN. The expansive size and high quality of moiré structures enables high-resolution mapping of the reciprocal space back-folded lattices and moiré mini band structures with low energy electron diffraction (LEED) and angle-resolved photoemission spectroscopy (ARPES). This technique will have broad applications in both fundamental studies and mass production of twistronic devices.