Engineering of Magnetic Coupling in Nanographene

Zheng, Yewei; Li, Can; Zhao, Yan; Beyer, Doreen; Wang, Guanyong; Xu, Chengyang; Yue, Xinlei; Chen, Yupeng; Guan, Dandan; Li, Yaoyi; Zheng, Hao; Liu, Canhua; Luo, Weidong; Feng, Xinliang; Wang, Shiyong; Jia, Jin‐Feng

doi:10.1103/physrevlett.124.147206

Cited by 55 publications

(50 citation statements)

References 56 publications

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“…2f)). The net single spin in nBNG monomers has also been carefully studied 30 , and similar observations have been obtained (cf. Supplementary Fig.…”

Section: Resultssupporting

confidence: 61%

“…As demonsrated by Li et al, the incorporation of pentagon rings in chiral graphene nanoribbons introduces one unpaired electron and two nearby spins can antiferromagnetic coupled together 23 . We recently demonstrated that nanographenes with such pentagon rings also host net spins and the coupling strength can be engineered by tailoring spin density overlap at the connecting region 30 .…”

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confidence: 99%

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Designer spin order in diradical nanographenes

Zheng

et al. 2020

Nat Commun

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The magnetic properties of carbon materials are at present the focus of intense research effort in physics, chemistry and materials science due to their potential applications in spintronics and quantum computing. Although the presence of spins in open-shell nanographenes has recently been confirmed, the ability to control magnetic coupling sign has remained elusive but highly desirable. Here, we demonstrate an effective approach of engineering magnetic ground states in atomically precise open-shell bipartite/nonbipartite nanographenes using combined scanning probe techniques and mean-field Hubbard model calculations. The magnetic coupling sign between two spins was controlled via breaking bipartite lattice symmetry of nanographenes. In addition, the exchange-interaction strength between two spins has been widely tuned by finely tailoring their spin density overlap, realizing a large exchange-interaction strength of 42 meV. Our demonstrated method provides ample opportunities for designer above-room-temperature magnetic phases and functionalities in graphene nanomaterials.

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“…2f)). The net single spin in nBNG monomers has also been carefully studied 30 , and similar observations have been obtained (cf. Supplementary Fig.…”

Section: Resultssupporting

confidence: 61%

mentioning

confidence: 99%

Designer spin order in diradical nanographenes

Zheng

et al. 2020

Nat Commun

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“…Recent advances of on-surface synthesis allow for tailoring -electron topologies at the single chemical bond level, and thus provide the ability to precisely engineer -electron magnetism in low-dimensional graphene nanostructures by introducing sublattice imbalance, topological frustration and topological defects [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] . Examples like triangulenes 41,43,48,51 , bowtie-shape nanographenes 47 , chiral graphene nanoribbons 45 , polymers 52 and nanographenes with topological defects 46,49 have been recently synthesized and characterized on surfaces. Similar as nanographenes, the porphyrin macrocycle is aromatic and can be interpreted as a multiple-bridged aromatic diaza [18]annulene system 53,54 .…”

Section: Introductionmentioning

confidence: 99%

Precise Control of π-Electron Magnetism in Metal-Free Porphyrins

Zhao

Jiang

et al. 2020

J. Am. Chem. Soc.

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The porphyrin marcocycle can stabilize a set of magnetic metal ions, thus introducing localized net spins near the center. However, it remains illusive but most desirable to introduce delocalized spins in porphyrins with wide implications, for example, for building correlated quantum spins. Here, we demonstrate that metal-free porphyrins host delocalized -electron magnetism as revealed by scanning probe microscopy and different level of theory calculations. Our results demonstrate that engineering of -electron topologies introduces spin polarized singlet state and delocalized net spins in metal-free porphyrins. In addition, the -electron magnetism can be switched on/off via STM manipulation by tunning the interfacial charge transfer. Our results provide an effective way to precisely control the -electron magnetism in metal-free porphyrins, which can be further extended to design new magnetic functionalities of porphyrin-based architectures.

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“…In addition to heteroatom doping, defect engineering, together with the structural design of zigzag edges, may provide an attractive method to tune the electronic and magnetic properties of Z‐NGs and ZGNRs [145, 146] . Our recent work shows that a five‐membered ring incorporated at the zigzag edge of nanographene can break the bipartite character of the sp 2 ‐carbon lattice and induce a single net spin of S=

1 / 2

[147, 148] . On the other hand, concealed non‐Kekulé NGs with intrinsic magnetism remain a class of less‐developed graphene nanostructures, and more effort will be needed for both solution and on‐surface synthesis.…”

Section: Discussionmentioning

confidence: 99%

Synthetic Tailoring of Graphene Nanostructures with Zigzag‐Edged Topologies: Progress and Perspectives

2020

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Experimental and theoretical investigations have revealed that the chemical and physical properties of graphene are crucially determined by their topological structures. Therefore, the atomically precise synthesis of graphene nanostructures is essential. A particular example is graphene nanostructures with zigzag‐edged structures, which exhibit unique (opto)electronic and magnetic properties owing to their spin‐polarized edge state. Recent progress in the development of synthetic methods and strategies as well as characterization methods has given access to this class of unprecedented graphene nanostructures, which used to be purely molecular objectives in theoretical chemistry. Thus, clear insight into the structure–property relationships has become possible as well as new applications in organic carbon‐based electronic and spintronic devices. In this Minireview, we discuss the recent progress in the controlled synthesis of zigzag‐edged graphene nanostructures with different topologies through a bottom‐up synthetic strategy.

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Engineering of Magnetic Coupling in Nanographene

Cited by 55 publications

References 56 publications

Designer spin order in diradical nanographenes

Designer spin order in diradical nanographenes

Precise Control of π-Electron Magnetism in Metal-Free Porphyrins

Synthetic Tailoring of Graphene Nanostructures with Zigzag‐Edged Topologies: Progress and Perspectives

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