1. bilayer phononic and photonic graphene: a new playground for twistronics

Yun Jing

Penn state university, USA

31 March 2022 Thu 9 am

                                      IBS Center for Theoretical Physics of Complex Systems (PCS), Administrative Office (B349), Theory Wing, 3rd floor

                                      Expo-ro 55, Yuseong-gu, Daejeon, South Korea, 34126 Tel: +82-42-878-8633                     

Twisted bilayer graphene (TBG), which entails two graphene sheets placed on top of each other with a small angle misalignment, has served as an emerging theoretical and experimental platform to study Van der Waals heterostructures owing to their intriguing electronic and optical properties. This field of research concerning how the twist between layers of 2D materials can alter and tailor their electronic behavior was coined “twistronics”. Meanwhile, artificial materials such as phononic crystals and photonic crystals have become a fertile playground for mimicking quantum-mechanical features of condensed matter systems and have revealed new routes to controlling classical waves. This talk will summarize our recent work on the analogue of bilayer graphene in classical wave systems, including acoustic waves, elastic waves, and electromagnetic waves. We will start with the analogue of AA- and AB-stacked bilayer graphene with both simulation and experimental results. We will then transition into the more complicated bilayer graphene including magic-angle bilayer graphene and SE (sublattice exchange)-even and SE-odd bilayer graphene. We will discuss their unique band structures and the wave behaviors associated with these bilayer graphene, such as energy confinement and topological corner modes. The application of these bilayer phononic and photonic graphene systems will also be discussed.