Two-leg t-J ladders are investigated in the framework of a combination of the phass string formulation and bond-operator representation. We develope a mean-field theory in the strong rung interaction regime, i.e. J⊥ ≫ J, t, which provides a unified description of the undoped insulating phase and the low doping spin gap phase. The ground state of the doped phase is intrinsically a superconductor with a d-wave symmetry gap driven by the t- term. The ground-state energy is in good agreement with numerical results. Phase separation is shown to occur beyond some critical value of J/t for given doping concentration. The local structure of hole pairs as well as the spectra of various spin and charge modes are also analyzed. copy; 2000 THE PHYSICAL SOCIETY OF THE REPUBLIC OF CHINA.
|頁（從 - 到）||313-321|
|期刊||Chinese Journal of Physics|
|出版狀態||Published - 2000 十二月 1|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)