双空位掺杂氟化石墨烯的电子性质和磁性

摘要

基于密度泛函理论,计算了外来原子X (Al, P, Ga, As, Si)双空位替代掺杂氟化石墨烯的电子特性和磁性。通过对计算结果分析发现,与石墨烯的双空位掺杂类似,氟化石墨烯的双空位掺杂也是一种较为理想的掺杂方式。通过不同原子掺杂,氟化石墨烯的电子性质与磁性均发生很大变化： Al和Ga掺杂使氟化石墨烯由半导体变为金属,并且具有磁性； P和As掺杂使氟化石墨烯变为自旋半导体； Si掺杂氟化石墨烯仍是半导体,只改变带隙且没有磁性。进一步讨论磁性产生机制获得了掺杂原子浓度与磁性的关系,并且发现不同掺杂情况的磁性是由不同原子的不同轨道电子引起的。双空位掺杂不仅丰富了氟化石墨烯的掺杂方式,其不同电磁特性也使此类掺杂结构在未来的电子器件中具有潜在应用。%According to the first principles, we investigate the structure, electronic, and magnetic properties of fluorinated graphene doped with external X (Al, P, Ga, As, Si) atoms at double vacancies, and find that like double vacancy doping of graphene, this kind of the fluorinated graphene divacancy substitution is also an ideal choice for substitutional doping. The results show that the electronic property and magnetic property of the fluorinated graphene both have large changes: the fluorinated graphene doped with Al (Ga) atoms can cause the semiconductor-to-metal transitions and induce magnetic moments. The fluorinated graphene doped with P (As) atoms becomes spin-polarized semiconductor. The Si doped fluorinated graphene keeps the semiconductor properties unchanged and has no magnetic moments. Through the further discussion about the mechanism of magnetism the relation between the doping concentration and magnetic property is obtained, and the magnetic properties in different doping situations are found to be caused by the different orbital electrons of different atoms. The divacancy substitutional doping behaviors enrich not only the doping ways of fluorinated graphene materials, but also its distinctive electronic and magnetic characteristics, which make this doping structure have potential applications in future electronic devices.