Our study sets forth a carbon-based two-dimensional (2D) kagome topological insulator without containing any metal atoms that aligns the Fermi level with the Dirac point without the need for doping, overcoming a significant bottleneck issue observed in 2D metal-organic framework-based kagome structures. Our 2D kagome structure, formed by creating patterned nano pores in the graphene sheet, nomenclatured as porous graphene-based kagome lattice (PGKL), is inspired by the recent bottom-up synthesis of similar structures. Because of the absence of mirror symmetry in our porous graphene, by considering only the first nearest neighbor intrinsic spin–orbit coupling (ISOC) within the tight-binding model, unlike the mostly used next nearest neighbor ISOC in the Kane–Mele model for graphene, PGKL exhibits distinctive band structures with Dirac bands amidst flatbands, allowing for the realization of topological states near the Fermi level. Delving into Berry curvature and Chern numbers provides a comprehensive understanding of the topological insulating properties of PGKL, offering valuable insights into 2D topological insulators. Analysis of the 1D ribbon structure underscores the emergence of topological edge states.

中文翻译：

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用多孔石墨烯设计二维 kagome 拓扑绝缘体


我们的研究提出了一种碳基二维 （2D） 笼目拓扑绝缘体，其中不包含任何金属原子，无需掺杂即可将费米能级与狄拉克点对齐，克服了在基于 2D 金属有机框架的笼目结构中观察到的重大瓶颈问题。我们的 2D 笼目结构是通过在石墨烯片上创建图案化的纳米孔而形成的，命名为多孔石墨烯基笼目晶格 （PGKL），其灵感来自最近自下而上合成的类似结构。由于我们的多孔石墨烯中没有镜像对称性，因此在紧密结合模型中仅考虑第一最近邻本征自旋-轨道耦合 （ISOC），与石墨烯的 Kane-Mele 模型中最常用的次最近邻 ISOC 不同，PGKL 表现出独特的能带结构，在平坦带中带有狄拉克能带，从而可以实现接近费米能级的拓扑状态。深入研究 Berry 曲率和 Chern 数可以全面了解 PGKL 的拓扑绝缘特性，为了解 2D 拓扑绝缘体提供有价值的见解。对 1D 带状结构的分析强调了拓扑边缘状态的出现。