Phase diagram of an extended t-U-J chain with frustrated exchange interaction

Abstract

Using the low-energy effective field theory scenario combined Abelian bosonization and renormalization-group techniques, we study the Hubbard chain with additional anisotropic nearest-neighbor and isotropic next-nearest-neighbor spin exchanges J and J′ in the weak-coupling regime. The spin correlations are non-critical due to the anisotropic J (Jxy ≠ Jz). The frustrating antiferromagnetic exchange J′ leads to an enhancement of the dimerized phase and induces a long-range charge-density-wave (CDW) phase. For smaller values of J′ (J′ < 2U/3), the quantum phase diagram consists of the insulating spin-density-wave ( SDW xy, SDW z) and bond-charge-density-wave (BCDW) phases and the triplet superconducting ( TS 0, TS ±) phase. For larger J′ (J′ ≥ 2U/3), a finite CDW phase appears. The result shows that the frustrated spin exchange J′ changes the topological structure of the usual t-U-J chain.