Turning 3D Molecular Crystals into 2D Moiré Superlattices with Properties Born Out of Bonding at the Angularly Stacked Interfaces

Angular stacking of two-dimensional (2D) nanoscale crystalline sheets into interacting superstructures, such as moiré superlattices, gives rise to potent quantum materials with unusual and remarkable properties. These superlattices are fabricated twist-stacked using mechanical positioning of the constituent lattices; however, their scalable fabrication is challenging. Chemistry-based methods in the liquid media may be helpful in this regard. Here, we report a generalized method for synthesizing multilayered moiré superlattices from covalent molecular crystals, ionic crystals, and metal complex crystals at moderate temperatures in the presence of ultrasonic waves with suitable solvent systems. We also report on the novel optical properties of specific superlattices, arising out of the angularly stacked interfaces. Furthermore, the observation of multilayered moiré superlattices of NaCl and KCl brings in a new perspective in the formation and stability of their 2D hexagonal lattices in such a superstructure. This discovery opens up new options for designing and fabricating moiré superlattices from various molecular materials and for studying their chemistry at the nanoscale.