Magic-Angle Twisted Bilayer Graphene as a Topological Heavy Fermion Problem

Magic-Angle Twisted Bilayer Graphene as a Topological Heavy Fermion Problem Magic-angle (θ=1.05°) twisted bilayer graphene (MATBG) has shown two seemingly contradictory characters: the localization and quantum-dot-like behavior in STM experiments, and delocalization in transport experiments. We construct a model, which naturally captures the two aspects, from the Bistritzer-MacDonald (BM) model in a first principle spirit. A set of local flat-band orbitals (f) centered at the AA-stacking region...