CM Theory Seminar | Topological and Fractional Electronic States in Graphene Heterostructures

Graphene is a highly tunable platform for studying the effects of electron-electron interactions in two dimensions. Encapsulation with a 2D dielectric (hexagonal boron nitride, hBN), and more recently the use of single-crystal graphite top and bottom gates have decreased the electronic disorder to a level suitable for the to study fragile and exotic strongly correlated states. Additionally, control of twist angle between closely-matched crystal lattices allows for unique control of electronic properties, leading to the “Hofstadter butterfly” and more recently unconventional superconductivity. I will describe newly discovered exotic fractional quantum Hall states and a class of related states called fractional Chern insulators, both in high quality graphene heterostructures. These measurements show that graphene is an intriguing platform for realizing new topological and fractional phases, and opens new routes towards realizing interesting quantum phase transitions and manipulating non-abelian quasiparticles for quantum computation.