通过sp3型掺杂获得高磁、铁磁性石墨烯的研究

sp3 type doping is considered to be an effective method to induce high-density localized spins on the basal plane of graphene sheets, and is the hottest issue foe exploring the realization of ferromagnetic graphene with high magnetization. Both F and OH have aroused many attentions and have been predicted to induce localized spins and create magnetic clusters through the following two cases: (1) generation of the stable OH clusters on the basal plane of graphene sheets; (2) formation of the stable triangle F domains on the basal plane of graphene sheets by annealing of fluorinated graphene at an appropriate temperature. In this project, we will induce high-density localized spins by the two typical sp3 dopants, and we will explore to realize ferromagnetic graphene with high magnetization by tailoring the doping contents. Based on the summary of our previous studies on the study of magnetic properties of the fluorinated and OH-doped graphene，we will first synthesize the fluorinated and OH-doped graphene with different F and OH doping contents by changing the reaction conditions. By detailed study, we will experimentally identify the dependences of the magnetization and Curie temperature on the doping contents, and the magnetic difference between F- and OH-doped graphene. For the ferromagnetic graphene obtained, we will investigate the spin transportation of the single sheet. We expect to reach a major breakthrough in the effective tailoring of the magnetic properties and spin transportation of graphene. Lastly, we will theoretically simulate the experimental results, and set up some theoretical models.

sp3型掺杂是实现在石墨烯基板面上引入高密度的局域自旋的有效途径，也是当今探索高磁、铁磁性石墨烯的热点。氟和羟基是两种最为引人关注的能引入局域自旋的sp3型掺杂剂，并能由以下两种情形引入自旋磁团簇：在石墨烯基板面上引入稳定分布的羟基团簇；和适当温度下退火氟化石墨烯而形成稳定的三角形氟畴。本项目拟分别借助这两种掺杂剂在石墨烯基板面上引入高密度局域自旋，进而探索通过调节掺杂量而获得高磁、铁磁性石墨烯为目标。在总结我们前期的氟和羟基掺杂石墨烯的磁性研究基础上，研究通过调变反应条件而分别得到具有不同氟和羟基掺杂量的两类石墨烯系列样品。通过磁性对比，从实验上揭示这两类石墨烯各自的掺杂量与磁化强度及居里点之间的依赖关系、及两类性能的差异。此外，对获得的铁磁性石墨烯单片器件的自旋输运性质进行初步研究。预期能在石墨烯磁性及自旋输运的调控研究方面有所突破。最后，进行相关的的理论模拟及建立理论模型。

在本项目的资助下，项目组瞄准石墨烯的磁性这一最近磁学界关注的热点，从实验和理论研究出发，采用sp3型掺杂剂羟基的掺杂引入磁矩。具体包括：1）通过把环氧基开环成羟基，我们在石墨烯氧化物的基板上引入了高浓度的局域磁矩；2）把氧化石墨烯量子点退火，使得羟基迁移到量子点的边沿，而其余的氧基团被去除，得到羟基保护的zigzag边沿；进而实验上明确了羟基能够在石墨烯的边沿引入局域磁矩；在此基础上3）我们把双层石墨烯纳米管剪开，得到氧化的双层石墨烯纳米带，并通过氩气中退火得到羟基保护的zigazag纳米带；并实现了文献报道的最强的室温铁磁性石墨烯，此纳米带具有环境条件下磁性的高稳定性；此外，4）我们还把羟基引入新型的二维碳材料石墨炔，发现羟基也可以在石墨炔的基面引入局域磁矩;且我们理论研究了该材料的磁性，发现该材料具有比石墨烯高得多的羟基迁移势垒，为二维碳材料的磁性研究开拓了新的思路。5）受实验研究结果启发，我们还理论设计了几种新型二维碳基自旋电子学材料。