Visualization of the flat electronic band in twisted bilayer graphene near the magic angle twist

Bilayer graphene was theorized to host a moiré miniband with flat dispersion if the layers are stacked at specific twist angles known as the “magic angles”. Recently, such twisted bilayer gra-phene (tBLG) with the first magic angle twist was reported to exhibit correlated insulating state and superconductivity, where the presence of the flat miniband in the system is thought to be es-sential for the emergence of these ordered phases in the transport measurements. Tunneling spectroscopy and electronic compressibility measurements in tBLG have revealed a van Hove sin-gularity that is consistent with the presence of the flat miniband. However, a direct observation of the flat dispersion in the momentum-space of such moiré miniband in tBLG is still elusive. Here, we report the visualization of the flat moiré miniband by using angle-resolved photoemission spectros-copy with nanoscale resolution (nanoARPES). The high spatial resolution in nanoARPES enabled the measurement of the local electronic structure of the tBLG. We clearly demonstrate the exist-ence of the flat moiré band near the charge neutrality for tBLG close to the magic angle at room temperature.