Macroscopic uniform 2D moir\'e superlattices with controllable angles

TL;DR

This paper introduces a scalable, high-quality method for creating large-area, precisely controlled 2D moiré superlattices with improved stability and reproducibility, enabling advanced studies and device applications.

Contribution

The authors develop a new strategy for fabricating macroscopic, uniform 2D moiré superlattices with controllable angles, overcoming limitations of traditional methods.

Findings

Achieved centimeter-scale moiré superlattices with high yield and stability.

Demonstrated versatility across various 2D materials.

Enabled detailed reciprocal space and band structure mapping.

Abstract

Moir\'e 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 moir\'e 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 moir\'e structures enables high-resolution mapping of the reciprocal space back-folded lattices and moir\'e 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.