Effect of correlation on nearly flat bands in twisted bilayer graphene*

Recently, correlated insulating phases were observed experimentally in twisted bilayer graphene (TBG) at different doping concentrations. To study possible mechanisms for insulating phases, we investigate electronic and magnetic properties in TBG by performing dynamical mean-field theory calculations based on a minimal tight-binding Hamiltonian. We study variation in the spectral function of the nearly flat bands for a range of local interaction parameters, electron filling, and temperature. We compare our results with experimental reports and discuss the possibility of Mott insulating phase in this system.