Spin-selective insulators in Bose-Fermi mixtures

Abstract: We investigate an imbalanced mixture composed of two-color fermions and scalar bosons in the hard-core limit, considering repulsive and attractive interspecies and intraspecies interactions. The interplay between commensurability, repulsive interactions and imbalance generates three insulating phases: a mixed Mott state and two spin-selective insulators characterized by the commensurability relations $\rho_B+\rho^{\uparrow,(\downarrow)}_F=1$. For an attractive coupling between fermions and bosons, we found the relations $\rho_B-\rho^{\uparrow,(\downarrow)}_F=0$ for the spin-selective insulators. State-of-the-art cold-atoms setups constitute ideal platforms to implement these unveiled insulating states and verify their commensurability relations.