Phase diagram of the Hubbard chain with symmetric density-dependent hopping

Abstract

By the bosonization and renormalization-group schemes, a half-filled Hubbard chain with density-dependent hopping is investigated at weak coupling. The model involved has an electron–hole symmetry and an SO(4) symmetry. The phase diagram consists of three different phases divided by a charge transition at on-site repulsion U=Uc and a spin transition at U=Us, with Us=−Uc=16π(tc−1), including a Mott insulator with the SDW correlation, a dimerized insulator with the BCDW correlation, and a Luttinger metal with the coexisting TS and BSDW correlations. The effective three-body repulsion (tc−1>0) and attraction (tc−1<0) induce the dimerized and metallic phases, respectively.