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arXiv 1708.02121cond-mat.mes-hall
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Lieb晶格上无序诱导的拓扑相变

Disorder-induced topological phase transitions on Lieb lattices

Rui Chen, Dong-Hui Xu, Bin Zhou

摘要:

基于电子Lieb晶格的最新实验实现和对物质拓扑态的研究兴趣,我们研究了自旋-轨道耦合Lieb晶格中Anderson无序驱动的拓扑相变.通过结合数值输运和自洽玻恩近似方法,我们发现时间反演不变和破缺Lieb晶格都可以存在无序诱导的带隙拓扑相,包括量子自旋霍尔绝缘体(QSHI)和量子反常霍尔绝缘体(QAHI)相.对于时间反演不变的情况,这种无序可以诱导拓扑相变直接从正常绝缘体(NI)的QSHI。而对于时间反演破缺情形,无序既可以诱导QAHI-QSHI相变,也可以诱导NI-QAHI-QSHI相变。值得注意的是,时间反转破缺的QSHI相可以由Anderson无序在没有时间反转对称性的自旋轨道耦合Lieb晶格上诱导。

英文摘要:

Motivated by the very recent experimental realization of electronic Lieb lattices and research interest on topological states of matter, we study the topological phase transitions driven by Anderson disorder on spin-orbit coupled Lieb lattices in the presence of spin-independent and dependent potentials. By combining the numerical transport and self-consistent Born approximation methods, we found that both time-reversal invariant and broken Lieb lattices can host disorder-induced gapful topological phases, including the quantum spin Hall insulator (QSHI) and quantum anomalous Hall insulator (QAHI) phases. For the time-reversal invariant case, this disorder can induce a topological phase transition directly from normal insulator (NI) to the QSHI. While for the time-reversal broken case, the disorder can induce either a QAHI-QSHI phase transition or a NI-QAHI-QSHI phase transition. Remarkably, the time-reversal broken QSHI phase can be induced by Anderson disorder on the spin-orbit coupled Lieb lattices without time-reversal symmetry.

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