Abstract By means of Scanning Tunneling Microscopy (STM) experiments and first-principles calculations, we demonstrate the synergetic effect of the combination of two different strategies to modify the properties of graphene supported on a strongly interacting substrate like Rh. A complete control of the corrugation and doping level is achieved combining the introduction of nitrogen defects and oxygen intercalation. Firstly, we show how to use ion bombardment to obtain purely-substitutional N-doped graphene on Rh(111) with tunable dopant concentration. In a second step, the interaction with the substrate is controlled by the amount of intercalated oxygen atoms. Unlike weakly interacting substrates, the highly corrugated structure of G/Rh(111) leads to remarkable variations of the electronic properties associated with nitrogen defects created in the high and low areas of the moire. After oxygen intercalation, the N-doped graphene layer decouples from the substrate preserving the incorporated nitrogen atoms, which display a subtle dependence of the STM contrast. First–principles calculations confirm the identification of substitutional N-defects and the recovery of the Dirac cone with a tunable shift governed by the nitrogen concentration. Our results support the combination of different modification techniques to tailor structural and electronic properties of graphene and other 2D materials.

中文翻译：

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结合氮置换缺陷和氧嵌入来控制石墨烯波纹和掺杂水平

摘要 通过扫描隧道显微镜 (STM) 实验和第一性原理计算，我们证明了两种不同策略组合的协同效应，以改变支持在强相互作用基底上的石墨烯的性质，如 Rh。结合引入氮缺陷和氧嵌入，实现了对波纹和掺杂水平的完全控制。首先，我们展示了如何使用离子轰击在具有可调掺杂浓度的 Rh(111) 上获得纯取代的 N 掺杂石墨烯。在第二步中，与衬底的相互作用由嵌入的氧原子的量控制。与弱相互作用底物不同，G/Rh(111) 的高度波纹结构导致与莫尔条纹高区和低区产生的氮缺陷相关的电子特性的显着变化。在氧嵌入之后，N 掺杂的石墨烯层与基底分离，保留了掺入的氮原子，这显示出 STM 对比度的微妙依赖性。第一性原理计算证实了替代氮缺陷的识别和狄拉克锥的恢复，其具有由氮浓度控制的可调位移。我们的结果支持结合不同的改性技术来定制石墨烯和其他二维材料的结构和电子特性。N 掺杂的石墨烯层与基底分离，保留了掺入的氮原子，这显示出 STM 对比度的微妙依赖性。第一性原理计算证实了替代氮缺陷的识别和狄拉克锥的恢复，其具有由氮浓度控制的可调位移。我们的结果支持结合不同的改性技术来定制石墨烯和其他二维材料的结构和电子特性。N 掺杂的石墨烯层与基底分离，保留了掺入的氮原子，这显示出 STM 对比度的微妙依赖性。第一性原理计算证实了替代氮缺陷的识别和狄拉克锥的恢复，其具有由氮浓度控制的可调位移。我们的结果支持结合不同的改性技术来定制石墨烯和其他二维材料的结构和电子特性。