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

• DOI: 10.1073/pnas.1720865115
• Publication Date: 2018-06-18T20:41:42Z
• Authors: Wei Yao; Eryin Wang; Changhua Bao; Yiou Zhang; Kenan Zhang; Kejie Bao; Chun Kai Chan; Chaoyu Chen; Jose Avila; Maria C. Asensio; Junyi Zhu; Shuyun Zhou
• Keywords: Bilayer graphene; Brillouin zone; Translational symmetry

The interlayer coupling can be used to engineer the electronic structure of van der Waals heterostructures (superlattices) obtain properties that are not possible in a single material. So far research has been focused on commensurate superlattices with long-ranged Moir\'e period. Incommensurate rotational symmetry but translational (in analogy quasicrystals) only rare nature, also interaction often assumed negligible due lack phase coherence. Here we report successful growth quasicrystalline 30{\deg} twisted bilayer graphene (30{\deg}-tBLG) which is stabilized by Pt(111) substrate, and reveal its structure. 30{\deg}-tBLG confirmed low energy electron diffraction intervalley double-resonance Raman mode at 1383 cm$^{-1}$. Moreover, emergence mirrored Dirac cones inside Brillouin zone each layer gap opening boundary suggest these two layers coupled via generalized Umklapp scattering mechanism, i.e. cone one reciprocal lattice vector other layer. Our work highlights important role incommensurate superlattices, thereby extending band engineering superstructures.