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arXiv 2302.01796physics.opticscond-mat.mes-hall
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具有拓扑平带的一类通用石墨烯边缘态的光子实现

Photonic realization of a generic type of graphene edge states exhibiting topological flat band

Shiqi Xia, Yongsheng Liang, Liqin Tang, Daohong Song, Jingjun Xu, Zhigang Chen

AI总结:

本研究利用光子平台理论与实验验证了细枝形石墨烯边缘态,发现其为与扶手椅边缘互补的通用HCL边缘,具有零能简并拓扑平带,可呈伸长或紧致局域化,拓宽了石墨烯边缘态认知,为人工类狄拉克材料波局域化提供新可能。

摘要:

在石墨烯边缘态研究中众所周知,切割蜂窝晶格(HCL)可得到三种类型的边缘:锯齿形、胡须形和扶手椅形。本文中,我们利用光子平台从理论上研究并通过实验演示了一类石墨烯边缘,即细枝形边缘,从而观测到了与此前观测到的边缘态截然不同的边缘态。我们的主要发现包括:(i)细枝边缘是与扶手椅边缘互补的一类通用HCL边缘,它通过选择合适的原胞形成,而非通过简单的晶格切割或Klein边缘修饰得到;(ii)细枝边缘态在整个布里渊区形成一条具有零能简并的完整平带,其特征是晶格哈密顿量具有非平凡的拓扑缠绕数;(iii)细枝边缘态可沿边界呈伸长分布或紧致局域化,同时展现出平带和拓扑特性。这类新型边缘态在激光直写的光子石墨烯中得以实现,并得到了数值模拟的充分验证。我们的研究结果可拓宽对石墨烯边缘态的理解,为人工类狄拉克材料中的波局域化带来新的可能。

英文摘要:

Cutting a honeycomb lattice (HCL) can end up with three types of edges (zigzag, bearded and armchair), as is well known in the study of graphene edge states. Here we theoretically investigate and experimentally demonstrate a class of graphene edges, namely, the twig-shaped edges, using a photonic platform, thereby observing edge states distinctive from those observed before. Our main findings are: (i) the twig edge is a generic type of HCL edges complementary to the armchair edge, formed by choosing the right primitive cell rather than simple lattice cutting or Klein edge modification; (ii) the twig edge states form a complete flat band across the Brillouin zone with zero-energy degeneracy, characterized by nontrivial topological winding of the lattice Hamiltonian; (iii) the twig edge states can be elongated or compactly localized along the boundary, manifesting both flat band and topological features. Such new edge states are realized in a laser-written photonic graphene and well corroborated by numerical simulations. Our results may broaden the understanding of graphene edge states, bringing about new possibilities for wave localization in artificial Dirac-like materials.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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