Cai, X., Zhou, J., Kong, P., Yi, W., Qin, H., Ni, Y., Chen, Y., & Wang, H. (2025). Composition-controllable topological nodal-line semimetals in covalent organic frameworks. Newton, 100299. https://doi.org/10.1016/j.newton.2025.100299
Abstract:
Covalent organic frameworks (COFs) are primarily normal insulators, with electronic structures modeled as composite bands above and below the Fermi level. To develop a strategy for creating COFs with unique topological states based on these models, we rationally design the first topological nodal-line semimetallic COF, termed HBAT-COF. Topology and frontier molecular orbital analysis reveal that N-containing heteroacene/acene-linked COFs typically exhibit an inherent diatomic Kagome six-band model. First-principles calculations show that the coupling between pyridinic-N atoms and Si-Br units drives topological phase transitions in HBAT-COF’s band structure. Notably, the Si-Br unit also enables composition-controllable semimetal states in disilabenzene-linked COFs lacking N atoms. This Si-Br-induced topological transition provides an approach to transforming normal insulating COFs into nodal-line semimetals with composite-band models.
License type:
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
Funding Info:
There was no specific funding for the research done