Correlation and superconductivity in magic-angle twisted graphene: Part 2

The abundance of emergent phenomena in twisted and untwisted van der Waals heterostructures has opened a new door to study strongly correlated physics in two-dimensional systems. In particular, the magic-angle twisted graphene family, which consists of systems where the adjacent graphene layers are twisted in an alternating fashion, has shown robust superconducting states. These superconducting states display orders of magnitude higher transition temperatures than the superconducting states shown in other graphene-based systems, despite the low carrier density. There have been striking observations, such as the violation of Pauli limit and the strong coupling strength of the Cooper pairs, which may limit the possible superconducting order parameters. Furthermore, the presence of nearby correlated resistive states and the topologically nontrivial phases has given rise to various theoretical interpretations on the ground state underlying the superconducting state. However, understanding the microscopic mechanism for such superconducting states and the relation to the nearby correlated phases is still far from complete. In this talk, we will present our most recent experimental results on the nature of the correlated and superconducting phases and their interactions in the extended magic-angle twisted graphene family.