过渡金属原子的单分散吸附及其对石墨烯电学性质的影响

项目名称： 过渡金属原子的单分散吸附及其对石墨烯电学性质的影响

项目编号： No.21503064

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 孔祥华

作者单位： 合肥工业大学

项目金额： 21万元

中文摘要： 自旋轨道耦合效应是实现电场调控电子自旋元器件的重要理论基础。石墨烯因其无质量的线性色散关系，是最有希望实现电子自旋应用的材料载体，但是石墨烯无磁性、无能隙、自旋轨道耦合效应极弱。理论研究发现，在石墨烯表面获得分散的金属原子吸附掺杂是实现强的自旋轨道耦合作用并进行相关量子输运的直接测量和调控的重要实验途径。然而，石墨烯表面金属原子吸附能低，易于迁移成团簇而难以分散。针对这一界面调控中的实验难点，本项目拟对石墨烯表面过渡金属的原子级分散展开研究，通过（1）对基底材料进行掺杂，即利用石墨烯晶格结构中的缺陷或异质原子提供较高的吸附能和稳定的吸附位点；（2）对金属原子进行化学修饰，即利用金属有机物分子二维自组装来固定单个金属原子；研究石墨烯基底和配体分子结构对金属原子吸附行为的影响，研究金属原子与石墨烯之间电荷转移强度对石墨烯电学性质的影响,为低能耗微纳电子自旋元器件的设计提供实验和理论依据。

中文关键词： 表面吸附；石墨烯掺杂；过渡金属原子；分子自组装；自旋轨道耦合效应

英文摘要： Spin-orbit coupling is the fundamental basis for electron-spin components controlled by electric field. The unique electronic structure with linear energy dispersion and massless Dirac fermions makes graphene the most promising material for spintronic devices, yet its zero-bandgap and weak intrinsic spin-orbit coupling remains the bottleneck to limit its application. Theoretical calculations predicted that a separate dispersion of individual metal atoms on graphene was an effective approach for realizing strong spin-orbit coupling of graphene and enabling directly measuring and tuning the related quantum transport. However, with a low adsorption energy, the metallic adatoms on graphene are apt to diffuse and form clusters or islands. To address this issue, we propose two ways aiming to the atomic-scale adsorption of transition metal atoms on graphene surface: (1) graphene substrate modification by vacancies or heteroatoms to enhance the adsorption energy of metallic adatoms and offer stable adsorption sites; (2) metallic atoms modification by organic-ligands for forming metallorganics thereby stabilizing the metallic atoms by means of molecular self-assembly. The effect of graphene structure and organic-ligands on the adsorption behavior of metallic atoms, and the effect of charge transfer between adatoms and graphene will be investigated. This study will contribute to the design of low-power micro-nano spintronic components from both theoretical and experimental aspects.

英文关键词： surface adsorption;graphene doping;transition metal atom(s);molecular self-assembly;spin-orbit coupling