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arXiv 1606.09161cond-mat.str-el
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Hofstadter-哈伯德模型中相互作用诱导的拓扑相和磁相

Interaction-Induced Topological and Magnetic Phases in the Hofstadter-Hubbard Model

Pramod Kumar, Thomas Mertz, Walter Hofstetter

摘要:

相互作用效应一直是当代感兴趣的主题,在拓扑相的物质。但在相互作用的存在下,精确确定拓扑不变量的一般形式是困难的,由于它们依赖于包含格林函数及其导数的多重积分。在这里,我们采用最近提出的“有效拓扑哈密顿量”的方法来探讨相互作用引起的拓扑相位的时间反演不变的Hofstadter-哈伯德模型。在这种方法中,自能的零频率部分足以确定正确的拓扑不变量。我们结合了拓扑哈密顿方法与本地自能近似,无论是静态和完整的动态自能使用动态平均场论(DMFT)评估,并提出了由此产生的相图中存在的多体相互作用。通过计算$\mathbb{Z}_2$不变量,研究了不同相互作用强度下量子自旋霍尔(QSH)态的出现。强关联和交错势的相互作用也诱导了具有相关一级跃迁的磁长程序。我们目前的交错磁化($m_s$),交错占用($n_s$),并在过渡的双重占用的结果。

英文摘要:

Interaction effects have been a subject of contemporary interest in topological phases of matter. But in the presence of interactions, the accurate determination of topological invariants in their general form is difficult due to their dependence on multiple integrals containing Green's functions and their derivatives. Here we employ the recently proposed "effective topological Hamiltonian" approach to explore interaction-induced topological phases in the time-reversal-invariant Hofstadter-Hubbard model. Within this approach, the zero-frequency part of the self-energy is sufficient to determine the correct topological invariant. We combine the topological Hamiltonian approach with the local self-energy approximation, both for the static and the full dynamical self-energy evaluated using dynamical mean field theory (DMFT), and present the resulting phase diagram in the presence of many-body interactions. We investigate the emergence of quantum spin Hall (QSH) states for different interaction strengths by calculating the $\mathbb{Z}_2$ invariant. The interplay of strong correlations and a staggered potential also induces magnetic long-range order with an associated first order transition. We present results for the staggered magnetization ( $m_s$ ), staggered occupancy ( $n_s$ ), and double occupancy across the transition.

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。

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