Bulk-edge correspondence in two-dimensional topological semimetals: A transfer matrix study of antichiral edge modes
Bulk-edge correspondence in two-dimensional topological semimetals: A transfer matrix study of antichiral edge modes
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DOI：
10.1103/physrevb.103.195310
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发表时间：
2020-12
影响因子：
3.7
通讯作者：
T. Mizoguchi;T. Koma
中科院分区：
文献类型：
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作者：
T. Mizoguchi;T. Koma
我们研究拓扑半金属中的边模，它具有普通半金属的能带结构，但可以用陈数来表征。更具体地说，我们专注于Qi-Wu-Zhang型正方形晶格模型和Haldane型蜂窝模型，这两种模型都表现出反手征边缘模式，其波包在条带的两个平行边缘处沿相同方向传播。为了获得边缘模式的这些解析解，我们应用了转移矩阵方法，该方法是在先前的工作[Phys. Rev. B 101，014442（2020）]中开发的。其结果是，我们表明，散装边缘对应被打破了一定范围内的模型参数。更准确地说，当增加的强度的跳跃振幅的Qi-Wu-Zhang型模型，边缘模式突然消失，虽然非平凡的陈数没有改变。在Haldane型模型中，改变模型参数，边缘模不一定消失，非平凡的Chern数也不改变。然而，从价带到导带的边缘模的能谱流在特定的模型参数下突然中断。
We study edge modes in topological semimetals, which have an energy band structure of ordinary semimetals but can be characterized by a Chern number. More specifically, we focus on a Qi-Wu-Zhang-type square-lattice model and a Haldane-type honeycomb model, both of which exhibit antichiral edge modes whose wave packets propagate in the same direction at both parallel edges of the strip. To obtain these analytical solutions of the edge modes, we apply the transfer matrix method, which was developed in the previous work [Phys. Rev. B 101, 014442 (2020)]. As a result, we show that the bulk-edge correspondence is broken down for a certain range of the model parameters. More precisely, when increasing the strength of a hopping amplitude of the Qi-Wu-Zhang-type model, the edge modes abruptly disappear, although the nontrivial Chern number does not change. In the Haldane-type model, for varying the model parameters, the edge modes do not necessarily disappear, and the nontrivial Chern number does not change. However, the energy spectral flows of the edge modes from the valence band to the conduction band are abruptly broken at a certain set of the model parameters.