Finite-sized graphene sheets, such as graphene nanoislands (GNIs), are promising candidates for practical applications in graphene-based nanoelectronics. GNIs with well-defined zigzag edges are predicted to have spin-polarized edge-states similar to those of zigzag-edged graphene nanoribbons, which can achieve graphene spintronics. However, it has been reported that GNIs on metal substrates have no edge states because of interactions with the substrate.We used a combination of scanning tunneling microscopy, spectroscopy, and density functional theory calculations to demonstrate that the edge states of GNIs on an Ir substrate can be recovered by intercalating a layer of Si atoms between the GNIs and the substrate. We also found that the edge states gradually shift to the Fermi level with increasing island size. This work provides a method to investigate spin-polarized edge states in high-quality graphene nanostructures on a metal substrate.

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有限尺寸的石墨烯片，例如石墨烯纳米岛（GNI），是在基于石墨烯的纳米电子学中实际应用的有希望的候选者。预测具有清晰锯齿形边缘的GNI具有与锯齿形边缘的石墨烯纳米带相似的自旋极化边缘状态，可以实现石墨烯自旋电子学。然而，据报道金属基体上的GNI由于与基体的相互作用而没有边缘状态，我们结合扫描隧道显微镜，光谱学和密度泛函理论计算证明了Ir基体上GNI的边缘状态可以通过在GNI和衬底之间插入一层Si原子来回收金属。我们还发现，随着岛的增大，边缘状态逐渐转变为费米能级。

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