The two-leg t-J ladder: A mean-field description

Abstract

Two-leg t-J ladders are investigated in the framework of a combination of the phase string formulation and bond-operator representation. We develope a mean-field theory in the strong rung interaction regime, i.e. $J_{\perp }\gg J,t$, which provides a unified description of the undoped insulating phase and the low doping phase --- the so-called C1S0 phase. Both of them are characterized by the resonating-valence-bond (RVB) order parameter, with gap opened up in all spin excitations. The ground state of the doped phase is intrinsically a superconductor with a d-wave symmetry, which is driven by the RVB correlations. 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. We also show that the spin gap in the doped phase is determined by quasi-particle-like excitations. The local structure of hole pairs as well as the spectra of various spin and charge modes are analyzed in comparison with other approaches.

33 pages, Revtex; 7 postscript figures

References in corpus (4)

• Absence of spin gap in the superconducting ladder compound Sr_2Ca_{12}Cu_{24}O_{41}
• Mean-Field Description of Phase String Effect in the $t-J$ Model
• Thermodynamics of the t-J Ladder: A Stable Finite Temperature Density Matrix Renormalization Group Calculation
• Phase Diagram of Coupled Ladders

Cited by in corpus (9)

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• Ground-state phase diagram of the extended two-leg $t$-$J$ ladder
• Breakdown of the Bloch-wave behavior for a single hole in a gapped antiferromagnet
• Intrinsic translational symmetry breaking in a doped Mott insulator
• Strong-coupling study of the pairing mechanism in pressurized La${}_3$Ni${}_2$O${}_7$
• Possible Liquid-Nitrogen-Temperature Superconductivity Driven by Perpendicular Electric Field in the Single-Bilayer Film of La${}_3$Ni${}_2$O${}_7$ at Ambient Pressure
• Hole-Doping Effects on a Two-dimensional Kondo Insulator
• Two-Hole and Four-Hole Bound States in a t-J Ladder at half-filling
• The t-Jz ladder