Recently, unconventional superconducting phase and correlated insulating phase in twisted bilayer graphene have attracted a lot of attention, which occurs at specific fillings and within a narrow range of twist angles (so-called magic angle). In this talk, I would like to address the following questions.
- What are the suitable models to describe the electronic states in twisted bilayer graphene?
- Why is the “magic angle” so special?
- What are the possible superconducting and insulating phases at half filling?
Related topics such as strain effect and other superlattices will also be discussed.