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arXiv · 2601.07083

Ferromagnetic Insulator to Metal Transition in Non-Centrosymmetric Graphene Nanoribbons

Aidan P. Delgado·Michael C. Daugherty·Weichen Tang·Steven G. Louie·Felix R. Fischer
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Abstract

Engineering sublattice imbalance within the unit cell of bottom-up synthesized graphene nanoribbons (GNRs) represents a versatile tool for realizing custom-tailored quantum nanomaterials. The interaction between low-energy zero-modes (ZMs) not only contributes to frontier bands but can form the basis for magnetically ordered phases. Here, we present the bottom-up synthesis of a non-centrosymmetric GNR that places all ZMs on the majority sublattice sites. Scanning tunneling microscopy and spectroscopy reveal that strong electron-electron correlations, leading to the Stoner magnetic instability, drive the system into a ferromagnetically ordered insulat-ing ground state featuring a sizeable band gap of Eg ~ 1.2 eV. At higher temperatures, a chemical transformation induces an insulator-to-metal transition that quenches the ferromagnetic order. Tight-binding (TB), density functional theory, and GW calculations corroborate our experimental observations. This work showcases how control over molecular symmetry, sublattice polarization, and ZM hybridiza-tion in bottom-up synthesized nanographenes can open a path to the exploration of many-body physics in rationally designed quantum materials.

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Aidan P. Delgado, Michael C. Daugherty, Weichen Tang, Steven G. Louie, Felix R. Fischer. 2026-01-11. Ferromagnetic Insulator to Metal Transition in Non-Centrosymmetric Graphene Nanoribbons. https://arxiv.org/abs/2601.07083

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