Frenche

In this paper, the electronic properties of 30 • twisted double bilayer graphene, which loses the translational symmetry due to the incommensurate twist angle, are studied by means of the tightbinding approximation. We demonstrate the interlayer decoupling in the low-energy region from various electronic properties, such as the density of states, effective band structure, optical conductivity and Landau level spectrum. However, at Q points, the interlayer coupling results in the appearance of new Van Hove singularities in the density of states, new peaks in the optical conductivity and importantly the 12-fold-symmetry-like electronic states. The k-space tight-binding method is adopted to explain this phenomenon. The electronic states at Q points show the charge distribution patterns more complex than the 30 • twisted bilayer graphene due to the symmetry decrease. These phenomena appear also in the 30 • twisted interface between graphene monolayer and AB stacked bilayer.