论文标题
扩展两腿$ t $ -j $ j $梯子的地面相图
Ground-state phase diagram of the extended two-leg $t$-$J$ ladder
论文作者
论文摘要
Inspired by the observation of a robust $d$-wave superconducting phase driven by tuning the next-nearest-neighbor (NNN) electron hopping in recent density matrix renormalization group (DMRG) studies of six- and eight-leg $t$-$J$ model, we systematically study the phase diagram of the two-leg $t$-$J$ ladder with the NNN couplings (including通过DMRG计算，NNN跳和自旋相互作用）在掺杂水平的大区域中。从半填充掺杂后，我们确定了路德emery液体（LEL）相，可以通过比较Luttinger参数$K_ρ$来区分为配对占主导地位和电荷密度优势式。随着nnn耦合的增长，配对相关性得到增强，并相应地增加了$k_ρ$，从而将系统从密度优势到配对优势制度驱动。在较大的掺杂区域中的Tomonaga-Luttinger液体（TLL）相中，我们确定了两个具有不同电荷密度相关特征的TLL状态。在季度填充（$ 1/2 $兴奋剂水平）上，我们发现开放系统中粘结能量的强二聚体顺序实际上是在代数上衰减的，因此并未表明自发的翻译对称性破坏。我们的结果表明，在两腿阶梯的LEL阶段，NNN耦合似乎扮演着与更广泛的$ t $ -j $ j $圆柱体相似的角色，并且对这个更可访问的系统的研究可以帮助理解出色的$ d $ - d $ - d $ - d $ -wave-wave supercondance occondy of the宽度系统。
Inspired by the observation of a robust $d$-wave superconducting phase driven by tuning the next-nearest-neighbor (NNN) electron hopping in recent density matrix renormalization group (DMRG) studies of six- and eight-leg $t$-$J$ model, we systematically study the phase diagram of the two-leg $t$-$J$ ladder with the NNN couplings (including NNN hopping and spin interaction) in a large region of doping level, by means of the DMRG calculations. Upon doping from half filling, we identify the Luther-Emery liquid (LEL) phase, which can be distinguished as the pairing-dominant and charge density-dominant regime by comparing the Luttinger parameter $K_ρ$. With the growing NNN couplings, pairing correlations are enhanced and correspondingly $K_ρ$ increases, driving the system from the density-dominant to the pairing-dominant regime. In the Tomonaga-Luttinger liquid (TLL) phase in the larger doping region, we identify two TLL regimes with different features of charge density correlation. At the quarter filling ($1/2$ doping level), we find that the strong dimer orders of bond energy in the open system actually decay algebraically and thus do not indicate a spontaneous translational symmetry breaking. Our results show that in the LEL phase of the two-leg ladder, the NNN couplings seem to play the similar role as that on the wider $t$-$J$ cylinder, and studies on this more accessible system can be helpful towards understanding the emergence of the remarkable $d$-wave superconducting phase on the wider system.
