May 1, 2018
(past)
noon
to 1:30 p.m.
60 St. George Street, MP 606
Michael Zaletel
Princeton University
Fractional quantum Hall physics could potentially occur not just in the flat Landau levels of an electron gas, but more generally in any band characterized by a topological Chern number. Such “Chern bands” can arise naturally from the interplay of a magnetic field and a periodic potential. Recently, graphene heterostructures have emerged as a platform for realizing Chern bands, by using a moire pattern between graphene and a substrate to engineer an artificial superlattice. Not only can the fractal structure of the Hofstadter butterfly be detected, the UCSB's Young Lab has now observed new gapped phases of matter which occur when the Chern bands of the butterfly are fractionally filled. I will discuss the theoretical interpretation of their results, which suggest graphene will prove a fruitful testbed for the physics of fractional Chern insulators.