Interlayer Coupling: An Additional Degree of Freedom in Two-Dimensional Materials.

Due to their layered nature, two-dimensional nanomaterials can stack into artificial material systems, with van der Waals interaction between the adjacent constituent layers. In such heterostructures, the physical properties are largely affected by the interlayer coupling and can thus be effectively tuned by a number of means. In this Perspective, we highlight four such experimental approaches: stacking order, electric field, intercalation, and pressure, and we discuss challenges and opportunities in future studies for van der Waals heterostructures.