  Metal-insulator transitions in a three-component Falicov-Kimball model are
investigated within the Kotliar-Ruckenstein slave boson mean-field approach.
The model describes a mixture of two interacting fermion atom species loaded
into an optical lattice at ultralow temperature. One species is two-component
atoms, which can hop in the optical lattice, and the other is single-component
atoms, which are localized. Different correlation-driven metal-insulator
transitions are observed depending on the atom filling conditions and local
interactions. These metal-insulator transitions are classified by the band
renormalization factors and the double occupancies of the atom species. The
filling conditions and the critical value of the local interactions for these
metal-insulator transitions are also analytically established. The obtained
results not only are in good agreement with the dynamical mean-field theory for
the three-component Falicov-Kimball model but also clarify the nature and
properties of the metal-insulator transitions in a simple physics picture.
