Quasicrystalline 30° twisted bilayer graphene as an incommensurate superlattice with strong interlayer coupling

Significance Interlayer interaction in van der Waals heterostructures could induce many exotic phenomena. Unlike commensurate heterostructures, incommensurate ones have often been neglected, due to the rarity in nature and the assumption of suppressed coherent interlayer movement of electrons. How the interlayer interaction affects the electronic structure of such a nonperiodic heterostructure is a fundamental question. In this work, by successfully growing 30°-twisted bilayer graphene (tBLG) as an example for incommensurate “heterostructure” with quasicrystalline order, we report the emergence of mirrored Dirac cones. We identify that these mirrored Dirac cones are a consequence of the interlayer interaction, showing its importance in the incommensurate structure, which has been overlooked before. These results broaden the application range of van der Waals heterostructure for future electronic devices.