High-Order van der Waals Superlattices and Artificial Quantum Solid Beyond Mechanical Exfoliation and Restacking

The advent of two-dimensional atomic crystals (2DACs) and van der Waals heterostructures (vdWHs) has inspired a new thinking on heterostructure construction beyond the limits of lattice matching requirement. However, the vdWHs explored to date have been largely limited to relatively simple systems with a small number of building blocks. The preparation of high-order vdW superlattices with a larger number of alternating units is exponentially more challenging due to the limited yield and scalability of the commonly used exfoliation-and-restacking strategy. Here I will discuss strategies to create high-order vdW superlattices (vdWSLs). First, by exploiting a capillary-force-driven rolling-up process, we show a series of synthetic VDWHs can be transformed into high-order vdWSLs with alternating atomic layers of widely variable material compositions, electronic band offset dimensions, chirality and topology. Alternatively, we further introduce a molecular intercalation approach to prepare a new family of hybrid superlattices consisting of alternating layers of covalently bonded 2D atomic layers and self-assembled molecular layers, which opens the door to exploit highly versatile molecular design strategies to tailor solid-state materials, enabling artificial materials with designable structural motifs and tunable electronic properties beyond the reach of conventional crystalline solids. We will particularly highlight a recent example of a new class of chiral molecular intercalation superlattices with robust chiral-induced spin selectivity.The formation of high-order vdW superlattices defines a rich artificial materials platform to unlock previously inaccessible physical limits and enable new device concepts beyond the reach of the existing materials.