In condensed matter physics, the moiré phenomenon is commonly discussed for two-dimensional materials. The effect occurs when there is mismatch between the lattice parameter or angle of the 2D layer and that of the underlying substrate,[1][2] or another 2D layer, such as in 2D material heterostructures.[3][4] The phenomenon is exploited as a means of engineering the electronic structure or optical properties of materials,[24] which some call moiré materials.