Mapping flat bands and correlated states in twisted trilayer graphene*

The twist angle between two van der Waals layers is a powerful tuning knob to engineer electronic band structure. In the limit of small interlayer twist, hybridization between layers can produce flat electronic bands, whereas a large twist angle leads to more decoupled layers. In this talk, I will discuss measurements of twisted trilayer graphene which realizes both flat and dispersive bands. We conduct electronic compressibility measurements with a scanning single electron transistor (SET) microscope to locally map how the band structure evolves as the inter-layer twist angles vary in space. We discover a range of “magic” angles for which electronic interaction effects are prominent for electrons and holes, respectively, leading to correlated phases at both low and high magnetic fields. I will discuss how these results clarify the role of interlayer twist in stabilizing distinct ground states in twisted graphene multilayer systems.