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arXiv 1003.2238cond-mat.str-el
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拓扑绝缘体与Hubbard相互作用的Mott物理

Topological Insulators and Mott Physics from the Hubbard Interaction

Stephan Rachel, Karyn Le Hur

摘要:

我们研究了具有内禀自旋轨道相互作用的蜂窝晶格上的哈伯德模型,作为存在相互作用的二维拓扑带绝缘体的范例。应用Hartree-Fock理论,从转子技术和拓扑参数的组合,我们表明,拓扑带绝缘相持续到相当强相互作用。然后,我们应用从转子平均场论,并找到一个莫特转变,在该转变的电荷自由度成为本地化的晶格网站。然而,自旋自由度仍然由原始Kane-Mele能带结构描述。该区域的规范场效应起着重要作用。当蜂窝层是孤立的,然后自旋扇区变得已经不稳定,朝着一个简单的平面尼尔秩序。相反,如果蜂窝晶格被具有无带隙自旋子的额外“屏蔽”层包围,则系统将支持边缘处具有无带隙自旋子的分数化拓扑绝缘体相。对于大的相互作用,我们推导出一个有效的自旋哈密顿量。

英文摘要:

We investigate the Hubbard model on the honeycomb lattice with intrinsic spin orbit interactions as a paradigm for two-dimensional topological band insulators in the presence of interactions. Applying a combination of Hartree-Fock theory, slave-rotor techniques, and topological arguments, we show that the topological band insulating phase persists up to quite strong interactions. Then we apply the slave-rotor mean-field theory and find a Mott transition at which the charge degrees of freedom become localized on the lattice sites. The spin degrees of freedom, however, are still described by the original Kane-Mele band structure. Gauge field effects in this region play an important role. When the honeycomb layer is isolated then the spin sector becomes already unstable toward an easy plane Neel order. In contrast, if the honeycomb lattice is surrounded by extra "screening" layers with gapless spinons, then the system will support a fractionalized topological insulator phase with gapless spinons at the edges. For large interactions, we derive an effective spin Hamiltonian.

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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