Composite super-moiré lattices in double aligned graphene heterostructures*

Van der Waals heterostructures, as vertical stacks assembled by different 2D crystals, have been widely used to produce combinations with predetermined functionalities. Apart from the selection and the sequence of 2D crystals, controlling the twist angle between stacking layers opened the use of another degree of freedom, especially for two crystals with similar lattice mismatch. Unlike the singly aligned heterostructures with one moire pattern, we reported a doubly aligned structure in which fully encapsulated graphene simultaneously aligned to the top and bottom hBNs. In this case, two periodic potentials due to the moire pattern are applied on graphene simultaneously. Their differential will create another set of supermoires, among which the one with the largest period can be independent of the difference in the lattice constants between two crystals and thus break through the restrictions of this lattice mismatch to achieve the period much larger than 14nm. This would open up the prospect for the design of graphene band reconstruction at arbitrary low Fermi energies. Based on this platform, some interesting phenomena on transport will be discussed in this presentation.