Abstract
Magic-angle twisted bilayer graphene, consisting of two graphene layers stacked at a special angle, exhibits superconductivity due to the maximized density of states at the energy of the flat band. Generally, experiments on twisted bilayer graphene have been performed using micrometer-scale samples. Here we report the fabrication of twisted bilayer graphene with an area exceeding 3 × 5 mm2 by transferring epitaxial graphene onto another epitaxial graphene, and observation of a flat band and large bandgap using angle-resolved photoemission spectroscopy. Our results suggest that the substrate potential induces both the asymmetrical doping in large angle twisted bilayer graphene and the electron doped nature of the flat band in magic-angle twisted bilayer graphene.
Highlights
Magic-angle twisted bilayer graphene, consisting of two graphene layers stacked at a special angle, exhibits superconductivity due to the maximized density of states at the energy of the flat band
In twisted bilayer graphene (TBG), the electronic structure can be modified by changing the rotation angle θ1,2
Twisting the layers is a fascinating technique to introduce another direction to electronic structure modification, in graphene, and in other two-dimensional materials, a phenomenon which has become known as twistronics[9]
Summary
Magic-angle twisted bilayer graphene, consisting of two graphene layers stacked at a special angle, exhibits superconductivity due to the maximized density of states at the energy of the flat band. In twisted bilayer graphene (TBG), the electronic structure can be modified by changing the rotation angle θ1,2. Nano-ARPES measurements of micrometer-scale TBG samples with a twist angle close to the magic-angle were performed, and the flat band almost at the Fermi energy was directly observed[15,16].
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