Topological edge states induced by the Zak phase in A3B monolayers
Topological edge states induced by the Zak phase in A3B monolayers
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DOI：
10.1103/physrevb.99.075426
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发表时间：
2019-02-19
影响因子：
3.7
通讯作者：
Wakabayashi, Katsunori
中科院分区：
文献类型：
--
作者：
Kameda, Tomoaki;Liu, Feng;Wakabayashi, Katsunori
在晶体系统中，电荷极化与由体能带拓扑确定的Zak相有关。非平凡电荷极化诱导伴随分数电荷的鲁棒边缘态。在Su-Schrieffer-Heeger模型中，电子跳跃的强调制即使在存在反转对称性的情况下也会引起非平凡的电荷极化。在这里，我们考虑一个双原子蜂窝晶格引入这样的强调制，即，a A（3）B表。通过调节A和B原子的跳跃比和在位势差，我们发现发生了以Zak相为特征的拓扑相变。此外，根据第一性原理计算，我们认为C3 N和BC 3是可能的现实材料。它们都显示拓扑边缘状态诱导的Zak相没有自旋轨道耦合和外部的领域，不同于传统的拓扑绝缘体。
In crystalline systems, charge polarization is related to the Zak phase determined by bulk band topology. Nontrivial charge polarization induces robust edge states accompanied by fractional charge. In the Su-Schrieffer-Heeger model, it is known that the strong modulation of electron hopping causes nontrivial charge polarization even in the presence of inversion symmetry. Here, we consider a biatomic honeycomb lattice to introduce such strong modulation, i.e., a A(3)B sheet. By tuning the hopping ratio and on-site potential difference between the A and B atoms, we show that the topological phase transition characterized by the Zak phase occurs. Furthermore, we propose that C3N and BC3 are possible realistic materials on the basis of first-principles calculations. Both of them display topological edge states induced by the Zak phase without spin-orbital couplings and external fields, unlike conventional topological insulators.