Interlayer coupling refers to the interaction between different layers of material in a heterostructure, such as two-dimensional materials or thin films stacked on top of each other. This coupling can have a significant impact on the properties of the material, influencing properties such as electronic structure, optical properties, and mechanical properties. Understanding and controlling interlayer coupling is important for designing novel materials with tailored properties for various applications, such as in electronics, photonics, and energy storage. Scientists study interlayer coupling using various experimental and theoretical techniques to elucidate the underlying mechanisms and optimize the performance of these materials.