Metal-insulator transition of the Kagome lattice fermions at 1/3 filling

Abstract

We discuss the metal-insulator transition of the spinless fermion model on the Kagom\'{e} lattice at 1/3-filling. The system is analyzed using exact diagonalization, the density-matrix renormalization group methods and the random phase approximation. In the strong-coupling region, the charge-ordered ground state is consistent with the predictions of the effective model with a plaquette order. We find that the qualitative properties of the metal-insulator transition are totally different depending on the sign of the hopping integrals, reflecting the difference of band structure at the Fermi level.