Phase transition of fractional Chern insulators: QED3 and beyond

          @misc{ pirsa_PIRSA:19040110,
            doi = {10.48660/19040110},
            url = {https://pirsa.org/19040110},
            author = {He, Yin-Chen},
            keywords = {Condensed Matter},
            language = {en},
            title = {Phase transition of fractional Chern insulators: QED3 and beyond},
            publisher = {Perimeter Institute},
            year = {2019},
            month = {apr},
            note = {PIRSA:19040110 see, \url{https://pirsa.org}}
          }
          

Abstract

Recent experiments in graphene heterostructures have observed Chern insulators - integer and fractional Quantum Hall states made possible by a periodic substrate potential. Here we study theoretically that the competition between different Chern insulators, which can be tuned by the amplitude of the periodic potential, leads to a new family of quantum critical points described by QED3-Chern-Simons theory. At these critical points, Nf flavors of Dirac fermions interact through an emergent U(1) gauge theory at Chern-Simons level K, and remarkably, the entire family (with any Nf or K) can be realized at special values of the external magnetic field. I will talk about the physical properties and microscopic realization of those critical points. We propose experiments on Chern insulators that could resolve open questions in the study of 2+1 dimensional conformal field theories and test recent duality inspired conjectures.