Deng Tianqi, Shi Wen, Wong Zicong Marvin, Wu Gang, Yang Xiaoping, Zheng Jin-Cheng, Pan Hui, Yang Shuo-Wang
Institute of High Performance Computing, Agency for Science, Technology and Research, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore.
School of Chemistry, Sun Yat-sen University, 510275 Guangzhou, China.
J Phys Chem Lett. 2021 Jul 29;12(29):6934-6940. doi: 10.1021/acs.jpclett.1c01731. Epub 2021 Jul 20.
The connection between electronic structures of metal-organic frameworks (MOFs) and their building subunits is a key cornerstone for rational MOF material design. Some two-dimensional conjugated MOFs were reported to be topological insulators. However, many of them are not intrinsic as the Fermi levels are far from the topological gaps. The subunit-to-MOF electronic orbital correspondence should be established to bridge their chemical structure and physical properties, thus understanding the design rules toward intrinsic topological insulators. Herein we reveal the fundamental role of the subunit-to-MOF symmetry relation in determining their orbital interaction and hybridization and, consequently, topological characteristics. In particular, such honeycomb-kagome MOFs possess delocalized symmetry-enforced nonbonding electronic states with the topological spin-orbit gap. The nonbonding nature of these states allows tailored band structure modulation through molecular structure and strain engineering, with the potential realization of an intrinsic metal-organic topological insulator.
金属有机框架（MOF）的电子结构与其构建亚基之间的联系是合理设计MOF材料的关键基石。据报道，一些二维共轭MOF是拓扑绝缘体。然而，其中许多并非本征拓扑绝缘体，因为费米能级远离拓扑能隙。应建立亚基与MOF的电子轨道对应关系，以弥合其化学结构与物理性质之间的差距，从而理解本征拓扑绝缘体的设计规则。在此，我们揭示了亚基与MOF对称关系在决定其轨道相互作用和杂化以及拓扑特性方面的基本作用。特别是，这种蜂窝 - Kagome MOF具有拓扑自旋轨道能隙的离域对称强制非键合电子态。这些态的非键合性质允许通过分子结构和应变工程进行定制的能带结构调制，从而有可能实现本征金属有机拓扑绝缘体。
