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arXiv 0907.2962cond-mat.str-el
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Mott物理与强自旋轨道相互作用材料的能带拓扑

Mott physics and band topology in materials with strong spin-orbit interaction

D. A. Pesin, Leon Balents

摘要:

最近的理论和实验表明,强自旋轨道耦合可以对弱相互作用固体的能带结构产生显著的定性影响。事实上,它导致了物质的一个独特的相,拓扑带绝缘体。本文考虑了自旋轨道耦合和强电子关联的联合作用,指出前者对关联驱动的Mott跃迁具有定量和定性的影响。作为一个具体的例子,我们采取Ir基高温超导体,其中的子系统的Ir 5d电子是已知的进行莫特过渡。在弱的电子-电子相互作用下,我们预测Ir电子在弱的自旋-轨道相互作用下处于金属相,而在强的自旋-轨道相互作用下处于拓扑带绝缘体相。非常一般地,我们表明,随着电子-电子相互作用的强度增加,有效的自旋-轨道耦合增强,增加了拓扑带绝缘体的域。此外,在我们的模型中,我们认为,随着相互作用的增加,拓扑带绝缘体转化为“拓扑莫特绝缘体“相,其特征在于无隙表面自旋唯一的激发。完整的相图还包括一个狭窄的区域的无带隙莫特绝缘体与自旋费米表面,和磁有序状态在更大的电子-电子相互作用。

英文摘要:

Recent theory and experiment have revealed that strong spin-orbit coupling can have dramatic qualitative effects on the band structure of weakly interacting solids. Indeed, it leads to a distinct phase of matter, the topological band insulator. In this paper, we consider the combined effects of spin-orbit coupling and strong electron correlation, and show that the former has both quantitative and qualitative effects upon the correlation-driven Mott transition. As a specific example we take Ir-based pyrochlores, where the subsystem of Ir 5d electrons is known to undergo a Mott transition. At weak electron-electron interaction, we predict that Ir electrons are in a metallic phase at weak spin-orbit interaction, and in a topological band insulator phase at strong spin-orbit interaction. Very generally, we show that with increasing strength of the electron-electron interaction, the effective spin-orbit coupling is enhanced, increasing the domain of the topological band insulator. Furthermore, in our model, we argue that with increasing interactions, the topological band insulator is transformed into a "topological Mott insulator" phase, which is characterized by gapless surface spin-only excitations. The full phase diagram also includes a narrow region of gapless Mott insulator with a spinon Fermi surface, and a magnetically ordered state at still larger electron-electron interaction.

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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