Interaction and spin-orbit effects on a kagome lattice at 1/3 filling

We investigate the competing effects of spin-orbit coupling and electron-electron interaction on a kagome lattice at 1/3 filling. We apply the cellular dynamical mean-field theory and its real-space extension combined with the continuous time quantum Monte Carlo method, and obtain a phase diagram including the effects of the interaction and the spin-orbit coupling at T=0.1t, where T is the temperature and t is the hopping energy. We find that without the spin-orbit coupling, the system is in a semi-metal phase stable against the electron-electron interaction. The presence of the spin-orbit coupling can induce a topological non-trivial gap and drive the system to a topological insulator, and as the interaction increases, a larger spin-orbit coupling is required to reach the topological insulating phase.