arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1409.3241cond-mat.str-el
收藏

准粒子在各向异性$t$ - $J$梯中的坍缩

Quasiparticle collapsing in an anisotropic $t$-$J$ ladder

Zheng Zhu, Zheng-Yu Weng

摘要:

准粒子坍缩是强关联电子系统研究的一个中心问题。在一维情况下,准粒子以自旋-电荷分离的形式坍缩已经得到了很好的证实,但是在高于一维的情况下,这个问题仍然是难以捉摸的。利用密度矩阵重整化群(DMRG)算法,我们证明了在各向异性的两足$t$ - $J$阶梯中,注入的单个空穴在强梯级极限下表现为一个定义明确的准粒子,但在量子临界点(QCP)处经历了一个有效质量向各向同性极限发散的“相变“.在跃迁之后,准粒子坍缩成一个自定域电荷(holon)和一个去精细自旋1/2(spinon)的复合体,伴随着两个空穴之间的结合能的大幅增强。进一步得到了多腿梯的相图,它将QCP外推到二维极限。还讨论了适用于任何维度的潜在新机制。

英文摘要:

Quasiparticle collapsing is a central issue in the study of strongly correlated electron systems. In the one-dimensional case, the quasiparticle collapsing in a form of spin-charge separation has been well established, but the problem remains elusive in dimensions higher than one. By using density matrix renormalization group (DMRG) algorithm, we show that in an anisotropic two-leg $t$-$J$ ladder, an injected single hole behaves like a well-defined quasiparticle in the strong rung limit, but undergoes a "phase transition" with the effective mass diverging at a quantum critical point (QCP) towards the isotropic limit. After the transition, the quasiparticle collapses into a composite object of a self-localized charge (holon) and a deconfined spin-1/2 (spinon), accompanied by a substantially enhanced binding energy between two holes. A phase diagram of multi-leg ladders is further obtained, which extrapolates the QCP towards the two-dimensional limit. The underlying novel mechanism generic for any dimensions is also discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑