arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2103.10862cond-mat.str-el
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相关性对长程跳跃二维Su-Schrieffer-Heeger模型的phase diagrams的影响

Effects of correlations on phase diagrams of the two-dimensional Su-Schrieffer-Heeger model with the longer-range hoppings

Tao Du, Yuexu Li, Helin Lu, Hui Zhang

摘要:

对于二维正方格子上的Su-Schrieffer-Heeger(SSH)模型,引入了两个保持手征对称性的第三近邻跳跃.与一维情形类似,长程跳跃可以驱动拓扑跃迁,并导致更大的拓扑不变量(二维SSH模型的矢量Berry相位)。我们从布洛赫哈密顿量的$ρ(k_l)$的缠绕模式得到相边界和拓扑相图。研究了相关性对扩展的二维SSH模型的影响。这种关联移动了相边界,导致了拓扑转变。在非相互作用相图中选取了几个特殊点来描述不同的相变,并从平凡相中找到了一个关联驱动的拓扑非平凡相.本文将从转子平均场方法应用到相互作用模型中,重点研究了物理电子的情况,即在我们的研究中避免了电荷自由度的Mott相变.

英文摘要:

For the Su-Schrieffer-Heeger (SSH) model on the two-dimensional square lattice, two third nearest neighbor hoppings which preserve chiral symmetry are introduced. Like the case of one dimension, the longer-range hopping can drive topological transitions and leads to the larger topological invariant (vectored Berry phase for the two dimensional SSH model). We obtain the phase boundaries and topological phase diagrams from the winding pattern of $ρ(k_l)$ of the Bloch Hamiltonian. Effects of correlations on the extended two dimensional SSH model are also investigated. The correlation shifts the phase boundaries and leads to topological transitions. Several special points in non-interacting phase diagrams are chosen to illustrate the different phase transitions and a correlations-driven topologically non-trivial phase from the trivial one is found. In this work, the slave-rotor mean field method is applied to the interacting model and we focus on the case of physical electrons, i.e. the Mott transition of charge degree of freedom is avoided in our investigations.

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