Brede Jens, Merino-Díez Nestor, Berdonces-Layunta Alejandro, Sanz Sofía, Domínguez-Celorrio Amelia, Lobo-Checa Jorge, Vilas-Varela Manuel, Peña Diego, Frederiksen Thomas, Pascual José I, de Oteyza Dimas G, Serrate David
Donostia International Physics Center, San Sebastián, E-20018, Spain.
Centro de Física de Materiales (MPC), CSIC-UPV/EHU, San Sebastián, E-20018, Spain.
Nat Commun. 2023 Oct 21;14(1):6677. doi: 10.1038/s41467-023-42436-7.
Low dimensional carbon-based materials can show intrinsic magnetism associated to p-electrons in open-shell π-conjugated systems. Chemical design provides atomically precise control of the π-electron cloud, which makes them promising for nanoscale magnetic devices. However, direct verification of their spatially resolved spin-moment remains elusive. Here, we report the spin-polarization of chiral graphene nanoribbons (one-dimensional strips of graphene with alternating zig-zag and arm-chair boundaries), obtained by means of spin-polarized scanning tunnelling microscopy. We extract the energy-dependent spin-moment distribution of spatially extended edge states with π-orbital character, thus beyond localized magnetic moments at radical or defective carbon sites. Guided by mean-field Hubbard calculations, we demonstrate that electron correlations are responsible for the spin-splitting of the electronic structure. Our versatile platform utilizes a ferromagnetic substrate that stabilizes the organic magnetic moments against thermal and quantum fluctuations, while being fully compatible with on-surface synthesis of the rapidly growing class of nanographenes.
低维碳基材料在开壳层π共轭体系中可表现出与p电子相关的本征磁性。化学设计能够对π电子云进行原子级精确控制，这使得它们在纳米级磁器件方面颇具潜力。然而，对其空间分辨自旋矩的直接验证仍然难以实现。在此，我们报告了通过自旋极化扫描隧道显微镜获得的手性石墨烯纳米带（具有交替锯齿形和扶手椅形边界的一维石墨烯条带）的自旋极化。我们提取了具有π轨道特征的空间扩展边缘态的能量相关自旋矩分布，从而超越了自由基或有缺陷碳位点处的局域磁矩。在平均场哈伯德计算的指导下，我们证明电子关联是电子结构自旋分裂的原因。我们的通用平台利用铁磁基底来稳定有机磁矩，使其免受热涨落和量子涨落的影响，同时与快速发展的纳米石墨烯类的表面合成完全兼容。
