Magic-angle twisted bilayer graphene exhibits correlated phenomena such as superconductivity and Mott insulating states related to the weakly dispersing flat band near the Fermi energy. Such a flat band is expected to be sensitive to both the moiré period and lattice relaxations. Thus, clarifying the evolution of the electronic structure with the twist angle is critical for understanding the physics of magic-angle twisted bilayer graphene. Here we combine nano-spot angle-resolved photoemission spectroscopy and atomic force microscopy to resolve the fine electronic structure of the flat band and remote bands, as well as their evolution with twist angle from 1.07° to 2.60°. Near the magic angle, the dispersion is characterized by a flat band near the Fermi energy with a strongly reduced band width. Moreover, we observe a spectral weight transfer between remote bands at higher binding energy, which allows to extract the modulated interlayer spacing near the magic angle. Our work provides direct spectroscopic information on flat band physics and highlights the important role of lattice relaxations.

魔角扭曲双层石墨烯表现出相关现象，例如与费米能附近的弱色散平带相关的超导性和莫特绝缘态。这种平带预计对莫尔周期和晶格弛豫都敏感。因此，阐明电子结构随扭曲角的演变对于理解魔角扭曲双层石墨烯的物理性质至关重要。在这里，我们结合纳米点角分辨光电子能谱和原子力显微镜来解析平带和远程带的精细电子结构，以及它们随扭转角从1.07°到2.60°的演化。在魔角附近，色散的特征是费米能附近的平带，带宽度大大减小。此外，我们观察到较高结合能的远程波段之间的光谱权重转移，这使得可以提取魔角附近的调制层间距。我们的工作提供了有关平带物理的直接光谱信息，并强调了晶格弛豫的重要作用。