Topological edge and corner states and fractional corner charges in blue phosphorene
Topological edge and corner states and fractional corner charges in blue phosphorene
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DOI：
10.1103/physrevb.105.075407
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发表时间：
2021-12
影响因子：
3.7
通讯作者：
Tenta Tani;Masaru Hitomi;T. Kawakami;M. Koshino
中科院分区：
文献类型：
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作者：
Tenta Tani;Masaru Hitomi;T. Kawakami;M. Koshino
利用第一性原理计算和紧束缚模型，从理论上研究了单层蓝磷(蓝磷)的边角态。我们发现在每个键中心的Wannier轨道的存在都会产生锯齿状和扶手椅状纳米带中的边缘态。对于非耦合的边缘轨道，边态的性质可以用一个简单的有效哈密顿量来很好地描述，其中边界附近的结构弛豫对边缘能带结构有显著的影响。对于角态，我们研究了由之字形和扶手椅边组成的两种角形结构，其中我们发现由于边缘和角形未耦合轨道的杂化，在体能隙中出现了多个角形结构。特别是在扶手椅角，我们证明角态正好出现在费米能级，这导致填充反常导致分数角电荷的出现。最后，我们讨论了蓝磷烯和黑磷烯之间的关系，结果表明，尽管它们的原子结构完全不同，但它们具有相同的Wannier轨道位置和相似的边/角态性质。
We theoretically study emergent edge and corner states in monolayer blue phosphorus (blue phosphorene) using the first-principles calculation and tight-binding model. We show that the existence of the Wannier orbitals at every bond center yields edge states both in zigzag and armchair nanoribbons. The properties of the edge states can be well described by a simple effective Hamiltonian for uncoupled edge orbitals, where the structural relaxation near the boundary significantly affects the edge band structure. For corner states, we examine two types of corner structures consisting of zigzag and armchair edges, where we find that multiple corner states emerge in the bulk gap as a consequence of hybridization of edge and corner uncoupled orbitals. In the armchair corner, in particular, we demonstrate that corner states appear right at the Fermi energy, which leads to the emergence of fractional corner charge due to filling anomaly. Finally, we discuss the relationship between blue phosphorene and black phosphorene, and show that two systems share the equivalent Wannier orbital positions and similar edge/corner state properties even though their atomic structures are totally different.