Group 14 element-based non-centrosymmetric quantum spin Hall insulators with large bulk gap
Group 14 element-based non-centrosymmetric quantum spin Hall insulators with large bulk gap
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DOI：
10.1007/s12274-015-0842-7
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发表时间：
2015-10-01
期刊：
影响因子：
9.9
通讯作者：
Heine, Thomas
中科院分区：
文献类型：
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作者：
Ma, Yandong;Kou, Liangzhi;Heine, Thomas
迄今为止，已经在第14族单元蜂窝晶格中实现了许多二维拓扑绝缘体，但它们都是反转对称的。在这里，基于第一性原理计算，我们预测了一个新的家庭的2D反转不对称TI具有相当大的散装间隙从105毫电子伏至284毫电子伏，在X2-GeSn（X = H，F，Cl，Br，I）单层，使它们在原则上适合于室温下的应用。在X =（F，Cl，Br，I）的原始X ~ 2-GeSn中发现了反转能带阶的非平凡拓扑特征，而H ~ 2-GeSn在8%的晶格膨胀下发生了非平凡能带反转.拓扑保护的边缘状态被确定在X2-GeSn与X =（F，Cl，Br，I），以及在应变H2-GeSn。更重要的是，这些系统的边缘，这表现出单狄拉克锥特性正好位于其体带隙的中间，是理想的无耗散传输。因此，第14族元素蜂窝晶格为量子态的操纵提供了一个迷人的游乐场。
To date, a number of two-dimensional (2D) topological insulators (TIs) have been realized in Group 14 elemental honeycomb lattices, but all are inversionsymmetric. Here, based on first-principles calculations, we predict a new family of 2D inversion-asymmetric TIs with sizeable bulk gaps from 105 meV to 284 meV, in X2-GeSn (X = H, F, Cl, Br, I) monolayers, making them in principle suitable for room-temperature applications. The nontrivial topological characteristics of inverted band orders are identified in pristine X2-GeSn with X = (F, Cl, Br, I), whereas H2-GeSn undergoes a nontrivial band inversion at 8% lattice expansion. Topologically protected edge states are identified in X2-GeSn with X = (F, Cl, Br, I), as well as in strained H2-GeSn. More importantly, the edges of these systems, which exhibit single-Dirac-cone characteristics located exactly in the middle of their bulk band gaps, are ideal for dissipationless transport. Thus, Group 14 elemental honeycomb lattices provide a fascinating playground for the manipulation of quantum states.