The effect of electron correlation on honeycomb lattice has attracted a lot of interest recently. In this talk, I will present the results of three analytical studies of correlated electrons on honeycomb lattice. In the first study, we provide an analytical argument for the absence of topological degeneracy in the "Mott insulating" state found recently in the Hubbard model on honeycomb lattice. In the second study, we propose a SU(2) generalization of staggered flux phase on honeycomb lattice, which reveals the close relation between the RVB physics on square lattice and honeycomb lattice. In the third study, we predict that the quarter-doped Hubbard model on honeycomb lattice will realize a magnetic ordered ground state with non-zero spin chirality and quantized Hall conductivity. It is argued that such an exotic state should be observable in quarter-doped graphene system.
Go to day