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arXiv · 2304.01641

Highly-Entangled Polyradical Nanographene with Coexisting Strong Correlation and Topological Frustration

Shaotang Song·Andrés Pinar Solé·Adam Matěj·Guangwu Li·Oleksandr Stetsovych·Diego Soler·Huimin Yang·Mykola Telychko·Jing Li·Manish Kumar·Jiri Brabec·Libor Veis·Jishan Wu·Pavel Jelinek·Jiong Lu
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Abstract

Open-shell benzenoid polycyclic aromatic hydrocarbons, known as magnetic nanographenes, exhibit unconventional p-magnetism arising from topological frustration or strong electronic-electron (e-e) interaction. Imprinting multiple strongly entangled spins into polyradical nanographenes creates a major paradigm shift in realizing non-trivial collective quantum behaviors and exotic quantum phases in organic quantum materials. However, conventional design approaches are limited by a single magnetic origin, which can restrict the number of correlated spins or the type of magnetic ordering in open-shell nanographenes. Here, we present a novel design strategy combing topological frustration and e-e interactions to fabricate the largest fully-fused open-shell nanographene reported to date, a 'butterfly'-shaped tetraradical on Au(111). We employed bond-resolved scanning tunneling microscopy and spin excitation spectroscopy to unambiguously resolve the molecular backbone and reveal the strongly correlated open-shell character, respectively. This nanographene contains four unpaired electrons with both ferromagnetic and anti-ferromagnetic interactions, harboring a many-body singlet ground state and strong multi-spin entanglement, which can be well described by many-body calculations. Furthermore, we demonstrate that the nickelocene magnetic probe can sense highly-correlated spin states in nanographene. The ability to imprint and characterize many-body strongly correlated spins in polyradical nanographenes not only presents exciting opportunities for realizing non-trivial quantum magnetism and phases in organic materials but also paves the way toward high-density ultrafast spintronic devices and quantum information technologies.

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Shaotang Song, Andrés Pinar Solé, Adam Matěj, Guangwu Li, Oleksandr Stetsovych, Diego Soler, Huimin Yang, Mykola Telychko, Jing Li, Manish Kumar, Jiri Brabec, Libor Veis, Jishan Wu, Pavel Jelinek, Jiong Lu. 2023-04-04. Highly-Entangled Polyradical Nanographene with Coexisting Strong Correlation and Topological Frustration. https://arxiv.org/abs/2304.01641

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