title: Incommensurate charge correlation and phase diagram of the one-dimensional superlattice Hubbard model at half-filling.
abstract: We study the phase diagram of a half-filled one-dimensional superlattice Hubbard model with an alternating orbital energy ± ϵ/2 and on-site Coulomb repulsion U(A) and U(B) using the density-matrix renormalization group and finite-size scaling analysis. For U(A) >> U(B), we observe an incommensurate charge correlation phase. For U(B) = 0, we find a transition from the band insulating phase to the correlated metallic phase at the critical point ϵ = U(A)/2. For U(B) > 0, we find three insulating phases as in the ionic Hubbard model. In the gapless region, the correlation functions exhibit the asymptotic behavior of power-law decay as in the Tomonaga-Luttinger liquid.
authors.affiliation: Department of Physics, Wuhan University, Wuhan, People's Republic of China.
authors.forename: Cheng-bo
authors.initials: CB
authors.lastname: Duan
authors.forename: Wei-zhong
authors.initials: WZ
authors.lastname: Wang