Investigation of the ground state of the anisotropic extended Hubbard chain at weak coupling

• We study the ground state of an anisotropic extended Hubbard chain at weak coupling.
• The anisotropic interactions have an important effect on the standard phase structure.
• The spin-dependent inter-site density repulsion leads to the BSDW phase.
• The inter-site AFM exchange enhances the controversial BOW phase.

We study a one-dimensional anisotropic extended Hubbard model, where the inter-site density (V) and exchange (J  ) interactions are spin-dependent. Use of bosonization and renormalization helps investigate phase diagram. At half filling, the ground state characterizes insulating phases. The spin-dependent repulsion leads to a bond-spin-density-wave (BSDW) phase. The antiferromagnetic exchange enhances the bond-order-wave (BOW) phase while weakens the charge-density-wave (CDW) phase. When J>4VJ>4V, the BSDW and CDW phases disappear. Away from half filling, the ground state exhibits superconducting behavior. The anisotropic interactions have an important effect on the phase structures.