Powered by Indico
v3.2.8
Speaker: Nicolas Regnault (ENS-CNRS-Princeton University)
Twisted bilayer graphene and Coulomb interaction: baking insulator states in six steps.
The twisted bilayer graphene (TBG) near the first magic angle hosts topological flat moiré electron bands, and exhibits a rich tunable strongly interacting physics. Correlated insulators and Chern insulators have been observed at various integer fillings. In this talk we will discuss the enhanced U(4) or U(4)xU(4) symmetries of the projected TBG Hamiltonian with Coulomb interaction in various combinations of the flat band and chiral limits. These enlarged symmetries allow us to identify exact or approximate ground or low-energy (Chern) insulator states at all the integer filling factors under a weak assumption that we justify numerically. We can also have access to exact charge and neutral excitations. We will present both perturbative and exact diagonalization results to discuss the fate of these model states in realistic cases.