Fabrication and Scanning Tunneling Spectroscopy of Magic Angle Twisted Bilayer Graphene*

Twisted bilayer graphene has recently gained significant attention due to the discovery of superconductivity and correlated insulating behavior near the magic angle of 1.1 degrees. Other twisted 2D van der Waals heterostructures are expected to host similar phenomena. Thus, methods for consistent and precise fabrication of twisted 2D materials are essential to enable their further study. We discuss the dry transfer technique that enables high accuracy rotational alignment that we have used to fabricate magic angle twisted bilayer graphene devices for scanning probe microscopy measurements. Using low temperature scanning tunneling microscopy and spectroscopy, we have verified the localization properties of the flat bands and directly probed the correlated insulating states at commensurate filings. These results can lead to a better understanding of the local electronic properties of magic angle twisted bilayer graphene.