Effect of singlet pairing hopping on the one-dimensional extended Hubbard model with spin exchange interaction

摘要

The ground-state properties of the one-dimensional (1D) t-U-J model with singlet pair hopping interaction are studied in the weak-coupling regime. The analysis of the model with U(1)-SU(2) symmetry is performed using the bosonization and renormalization-group approaches. At half filling the phase diagram is shown to consist of three different insulating states corresponding to the Peierls dimerized bondcharge-density-wave (BCDW) phase, the spin-density-wave (SDW) phase and the bond-spin-density-wave (BSDW) phase, and two different superconducting states with the singlet-superconducting (SS) phase and the triplet-superconducting (TS) phase. Moreover, the SDW, BSDW and TS phases are all degenerated. The result indicates that the pair hopping interaction P has a strong effect on the ground-state properties of 1D correlated electron systems.