Mott transitions in three-component Falicov-Kimball model

Abstract

Metal-insulator transitions are studied within a three-component Falicov-Kimball model which mimics a mixture of one-component and two-component fermionic particles with local repulsive interactions in optical lattices. Within the model the two-component fermionic particles are able to hop in the lattice, while the one-component fermionic particles are localized. The model is studied by using the dynamical mean-field theory with exact diagonalization. Its homogeneous solutions establish Mott transitions for both commensurate and incommensurate fillings between one third and two thirds. At commensurate one third and two thirds fillings the Mott transition occurs for any density of hopping particles, while at incommensurate fillings the Mott transition can occur only for density one half of hopping particles. At half filling, depending on the repulsive interactions the reentrant effect of the Mott insulator is observed. As increasing local interaction of hopping particles, the first insulator-metal transition is continuous, whereas the second metal-insulator transition is discontinuous. The second metal-insulator transition crosses a finite region where both metallic and insulating phase coexist. At third filling the Mott transition is established only for strong repulsive interactions. A phase separation occurs together with the phase transition.