Quantum Cafe Webinar: Abhay Pasupathy

Title: Twistons in the Magic Sea

Abstract: The latest entry into the moiré graphene family is twisted trilayer graphene. This material consists of three sheets of graphene, and features a “magic” angle where the fermi velocity goes to zero like in twisted bilayer graphene. This magic condition is reached theoretically when the top and bottom layers are aligned with each other, and the middle layer is misaligned by about 1.5 degrees with respect to the other two. Soon after the theoretical predictions, two experiments have shown that this system also displays superconductivity, like twisted bilayer graphene. Exotic explanations for the mechanism of superconductivity in this material have been proposed. However, experimental verification of even the basic electronic structure on which these theories are based is not currently available. I will discuss my group’s recent STM experiments of these samples and their spectroscopic properties. The experimental reality of these samples is seen to be rather different from theory both at the level of atomic structure and electronic properties!

For Zoom details please contact Mary Kate Hennelly at [email protected]