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Model Hamiltonian for the Quantum Anomalous Hall State in Iron-Halogenide
Chinese Physics Letters ( IF 3.5 ) Pub Date : 2020-09-01 , DOI: 10.1088/0256-307x/37/9/097301
Qian Sui 1 , Jiaxin Zhang 1, 2 , Suhua Jin 1 , Yunyouyou Xia 1 , Gang Li 1, 3
Affiliation  

We examine quantum anomalous Hall (QAH) insulators with intrinsic magnetism displaying quantized Hall conductance at zero magnetic fields. The spin-momentum locking of the topological edge stats promises QAH insulators with great potential in device applications in the field of spintronics. Here, we generalize Haldane's model on the honeycomb lattice to a more realistic two-orbital case without the artificial real-space complex hopping. Instead, we introduce an intraorbital coupling, stemming directly from the local spin-orbit coupling (SOC). Ourd(xy)/d(x)(2)-y(2)model may be viewed as a generalization of the bismuthenep(x)/p(y)-model for correlatedd-orbitals. It promises a large SOC gap, featuring a high operating temperature. This two-orbital model nicely explains the low-energy excitation and the topology of two-dimensional ferromagnetic iron-halogenides. Furthermore, we find that electronic correlations can drive the QAH states to ac= 0 phase, in which every band carries a nonzero Chern number. Our work not only provides a realistic QAH model, but also generalizes the nontrivial band topology to correlated orbitals, which demonstrates an exciting topological phase transition driven by Coulomb repulsions. Both the model and the material candidates provide excellent platforms for future study of the interplay between electronic correlations and nontrivial band topology.

中文翻译:

铁卤化物中量子反常霍尔态的模型哈密顿量

我们检查具有内在磁性的量子反常霍尔 (QAH) 绝缘体,在零磁场下显示量子化霍尔电导。拓扑边缘统计的自旋动量锁定有望使 QAH 绝缘体在自旋电子学领域的器件应用中具有巨大潜力。在这里,我们将 Haldane 在蜂窝晶格上的模型推广到更现实的双轨道情况,而无需人工实空间复数跳跃。相反,我们引入了一种直接源自局部自旋轨道耦合 (SOC) 的轨道内耦合。Ourd(xy)/d(x)(2)-y(2) 模型可以看作是相关轨道的 bismuthenep(x)/p(y) 模型的推广。它具有较大的 SOC 间隙,具有较高的工作温度。这种双轨道模型很好地解释了二维铁磁卤化铁的低能激发和拓扑结构。此外,我们发现电子相关性可以将 QAH 状态驱动到 ac=0 相位,其中每个波段都带有一个非零的陈数。我们的工作不仅提供了一个现实的 QAH 模型,而且将非平凡的带拓扑推广到相关轨道,这证明了由库仑排斥驱动的令人兴奋的拓扑相变。模型和候选材料都为未来研究电子相关性和非平凡能带拓扑之间的相互作用提供了极好的平台。我们的工作不仅提供了一个现实的 QAH 模型,而且将非平凡的带拓扑推广到相关轨道,这证明了由库仑排斥驱动的令人兴奋的拓扑相变。模型和候选材料都为未来研究电子相关性和非平凡能带拓扑之间的相互作用提供了极好的平台。我们的工作不仅提供了一个现实的 QAH 模型,而且将非平凡的带拓扑推广到相关轨道,这证明了由库仑排斥驱动的令人兴奋的拓扑相变。模型和候选材料都为未来研究电子相关性和非平凡能带拓扑之间的相互作用提供了极好的平台。
更新日期:2020-09-01
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