Atomic arrangements of quasicrystal bilayer graphene: Interlayer distance expansion
Y. Fukaya, Yuhao Zhao, Hyun-Woo Kim, Joung Real Ahn, Hirokazu Fukidome, Iwao Matsuda
Abstract
Bilayer graphene exhibits outstanding characteristics that can be modified by adjusting the twist angle between two layers. An exact ${30}^{\ensuremath{\circ}}$-twisted bilayer graphene forms a material comprising two-dimensional quasicrystals accompanied by a relativistic Dirac fermion. In this study, the atomic arrangements of quasicrystal bilayer graphene on a SiC(0001) substrate are identified using positron diffraction. The interlayer distance in quasicrystal bilayer graphene is determined to be 3.46 \AA{}, revealing an expansion of 0.17 \AA{} as compared with that of Bernal-stacked bilayer graphene. This result provides important insights for elucidating the origin of the magnitude of coupling between graphene layers.