Zheng Yuqiang, Li Can, Xu Chengyang, Beyer Doreen, Yue Xinlei, Zhao Yan, Wang Guanyong, Guan Dandan, Li Yaoyi, Zheng Hao, Liu Canhua, Liu Junzhi, Wang Xiaoqun, Luo Weidong, Feng Xinliang, Wang Shiyong, Jia Jinfeng
Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, 200240, Shanghai, China.
Center for Advancing Electronics Dresden and Department of Chemistry and Food Chemistry, Technische Universität Dresden, 01062, Dresden, Germany.
Nat Commun. 2020 Nov 27;11(1):6076. doi: 10.1038/s41467-020-19834-2.
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.
由于碳材料在自旋电子学和量子计算中的潜在应用，其磁性能目前是物理、化学和材料科学领域深入研究的重点。尽管最近已证实开壳层纳米石墨烯中存在自旋，但控制磁耦合符号的能力仍然难以捉摸，却又备受期待。在此，我们展示了一种利用扫描探针技术和平均场哈伯德模型计算相结合的方法，在原子精确的开壳层二分/非二分纳米石墨烯中设计磁基态。通过破坏纳米石墨烯的二分晶格对称性来控制两个自旋之间的磁耦合符号。此外，通过精细调整两个自旋的自旋密度重叠，可广泛调节它们之间的交换相互作用强度，实现了高达42 meV的大交换相互作用强度。我们所展示的方法为设计石墨烯纳米材料中高于室温的磁性相和功能提供了充足的机会。
