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arXiv · 2512.08680

Engineering Topological Bands in Strained Covalent Organic Frameworks

Rebecca Peake·Zoé Truyens·Jan Mol·Christian B Nielsen·David Beljonne·David Cornil·Owen Benton
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Abstract

The tunability of covalent organic frameworks (COFs) opens opportunities to engineer topological electronic phases, including topological insulators (TIs) and higher-order topological insulators (HOTIs)--materials that host in-gap states localized at their edges, hinges, or corners. Here we explore how chemically feasible perturbations can drive triazine-based COFs (CTFs) into topological regimes. Using a tight-binding model on the Honeycomb lattice inspired by the frontier electronic states of CTFs, we show that introducing an effective uniaxial strain--implemented as a modulation of electron hopping on a subset of bonds--can generate a series of distinct topological band structures. This effect can be realized in practice through chemical substitution of linkers along the strained bonds. First-principles calculations demonstrate that replacing biphenyl with pyrene linkers drives a CTF to the brink of a HOTI phase, suggesting a viable route toward topological band-structure engineering in COFs.

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Rebecca Peake, Zoé Truyens, Jan Mol, Christian B Nielsen, David Beljonne, David Cornil, Owen Benton. 2025-12-09. Engineering Topological Bands in Strained Covalent Organic Frameworks. https://arxiv.org/abs/2512.08680

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