Topological junction states and their crystalline network in systems with chiral symmetry: Application to graphene nanoribbons
Topological junction states and their crystalline network in systems with chiral symmetry: Application to graphene nanoribbons
复制标题
DOI：
10.1103/physrevb.101.205311
复制
发表时间：
2020-04
影响因子：
3.7
通讯作者：
Gen Tamaki;T. Kawakami;M. Koshino
中科院分区：
文献类型：
--
作者：
Gen Tamaki;T. Kawakami;M. Koshino
我们建立了一个基于$Z$分类的一般理论框架来计算手性对称一维系统交界处的拓扑束缚态数。该公式适用于由任意数量的通道和任意接头结构组成的一般多路结。利用该公式，我们计算了半导体石墨烯纳米带各种类型双向结和三向结的零能束缚态。然后，我们考虑了石墨烯纳米带的周期性二维网络，并表明拓扑结态在体能隙内形成孤立的能带，可以看作是有效原子的二维晶体。根据单个结的$Z$数，我们有一组不同的有效原子轨道，从而产生各种类型的纳米级超材料，这些超材料通常伴随着平带。该系统将为量子模拟器在不同晶格上模拟强相互作用费米子系统提供一个理想的平台。
We develop a general theoretical framework based on $Z$-classification to count the number of topological bound states at a junction of chiral-symmetric one-dimensional systems. The formulation applies to general multiway junctions composed of an arbitrary number of channels and an arbitrary joint structure. By using the formula, we calculate the zero-energy bound states in various types of two-way and three-way junctions of semiconducting graphene nanoribbons. We then consider periodic two-dimensional networks of graphene nanoribbons, and show that the topological junction states form isolated energy bands inside the bulk energy gap, which can be viewed as a two-dimensional crystal of the effective atoms. Depending on the $Z$ number of a single junction, we have a different set of effective atomic orbitals, resulting in various types of nanoscale metamaterials, which are often accompanied by flat bands. The system would provide an ideal platform for quantum simulator to emulate a strongly-interacting fermion system on various types of lattices.