Graphene nanoribbons (GNRs), low-dimensional platforms for carbon-based electronics, show the promising perspective to also incorporate spin polarization in their conjugated electron system. However, magnetism in GNRs is generally associated to localized states around zigzag edges, difficult to fabricate and with high reactivity. Here we demonstrate that magnetism can also be induced away from physical GNR zigzag edges through atomically precise engineering topological defects in its interior. A pair of substitutional boron atoms inserted in the carbon backbone breaks the conjugation of their topological bands and builds two spin-polarized boundary states around. The spin state was detected in electrical transport measurements through boron-substituted GNRs suspended between tip and sample of a scanning tunneling microscope. First-principle simulations find that boron pairs induce a spin 1, which is modified by tuning the spacing between pairs. Our results demonstrate a route to embed spin chains in GNRs, turning them basic elements of spintronic devices.

中文翻译：

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石墨烯纳米带中硼取代引起的拓扑边界态的磁性

石墨烯纳米带（GNR）是用于碳基电子产品的低尺寸平台，显示了将自旋极化也纳入其共轭电子系统的广阔前景。然而，GNR中的磁性通常与之字形边缘周围的局部状态相关，难以制造且具有高反应性。在这里，我们证明了磁性也可以通过其内部原子精确的工程拓扑缺陷从物理GNR之字形边缘感应出来。插入碳骨架中的一对取代硼原子破坏了它们的拓扑带的共轭，并在其周围建立了两个自旋极化的边界态。在电迁移测量中，通过悬浮在扫描隧道显微镜的尖端和样品之间的硼取代的GNR来检测自旋状态。第一性原理模拟发现，硼对诱导自旋1，可通过调节对之间的间距进行修饰。我们的研究结果证明了将自旋链嵌入GNR的途径，使它们成为自旋电子设备的基本元素。