arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2406.03529cond-mat.mes-hallcond-mat.mtrl-sci
收藏

拓扑材料中的环态

Ring states in topological materials

Columbia University(哥伦比亚大学);Flatiron Institute(平顿研究所);Tel Aviv University(特拉维夫大学);Princeton University(普林斯顿大学);Donostia International Physics Center(圣塞巴斯蒂安国际物理中心);IKERBASQUE, Basque Foundation for Science(伊克尔巴斯基克科学基金会);Weizmann Institute of Science(魏茨曼科学研究所)

Raquel Queiroz, Roni Ilan, Zhida Song, B. Andrei Bernevig, Ady Stern

AI总结:

本文提出拓扑材料中的“环态”概念,揭示其由能带拓扑在杂质格林函数中施加零点而被钉扎于拓扑能隙内,并证明环态可作为边界模式的基本构建单元,为理解体-边界对应提供新框架。

摘要:

带隙内态在半导体中普遍存在,通常可以在有效质量近似下用类氢模型很好地描述。然而,当杂质很强时,它们会显著扰动所有动量本征态,导致深能级束缚态,这些束缚态揭示了未扰动能带结构的全局性质。在这项工作中,我们发现能带波函数的拓扑可以在拓扑能隙内的杂质投影格林函数中施加零点。这些零点可以被解释为谱吸引子,定义了在存在无限强局域杂质时带隙内态被钉扎的能量。它们的钉扎能量通过最小化能带本征态对带隙内态的能级排斥来求得。我们将这些态称为环态,其特征是混合能带性质和杂质位点处的节点,这保证了它们与裸杂质本征态的正交性以及对杂质强度的弱能量依赖性。我们证明,无法构造对称且指数局域的 Wannier 函数确保了环态的拓扑保护。将环态连接起来,对于任何受拓扑保护的相,都可以恢复边缘态或表面态。因此,环态也可以被视为边界模式的基本构建单元,为理解体-边界对应提供了一个框架。

英文摘要:

Ingap states in semiconductors are commonly characterized by hydrogenic models within the effective mass approximation. However, when impurities are strong, this description fails. The bound states are non-perturbative with energy pinned to a zero of the impurity-projected Green's function. We show that in the presence of Wannier obstructions, such zeros are irremovable. That is, no symmetric, gap-preserving deformation of the bulk can return the ingap state to the band continuum. We call these states ring states: their wavefunctions show a node at the impurity site, and their mixed band character is set by minimizing the level repulsion exerted by the bands above and below the gap. In Chern insulators, the band mixing endows occupied ring states with local circulating currents, remnant of a small edge mode surrounding the vacancies. Clusters of vacancies bind ring states that hybridize to form dispersive chiral edge modes, providing a real-space view of bulk-boundary correspondence.

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。

↑