Electronic and structural characterization of divacancies in irradiated graphene
Electronic and structural characterization of divacancies in irradiated graphene
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DOI：
10.1103/physrevb.85.121402
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发表时间：
2012-03-08
影响因子：
3.7
通讯作者：
Yndurain, Felix
中科院分区：
文献类型：
--
作者：
Ugeda, Miguel M.;Brihuega, Ivan;Yndurain, Felix
我们对碳双空位进行了全面的研究，碳双空位是一种预计会对石墨烯性能产生重大影响的点缺陷。不同基底上辐照石墨烯的低温扫描隧道显微镜成像使我们能够识别常见的双重对称点缺陷。我们的第一性原理计算表明，这种缺陷的结构在由两个五边形和一个八边形形成的重新排列的原子网络中容纳了两个相邻的缺失原子，没有悬空键。对近乎理想的石墨烯中产生的双空位的扫描隧道光谱测量显示，电子光谱以空态共振为主，这归因于π电子性质的近乎平坦的自旋简并带。虽然计算的电子结构排除了双空位周围磁矩的形成，但费米能级附近电子共振的产生揭示了双空位是调节石墨烯系统中电子传输特性的关键点缺陷。
We provide a thorough study of a carbon divacancy, a point defect expected to have a large impact on the properties of graphene. Low-temperature scanning tunneling microscopy imaging of irradiated graphene on different substrates enabled us to identify a common twofold symmetry point defect. Our first-principles calculations reveal that the structure of this type of defect accommodates two adjacent missing atoms in a rearranged atomic network formed by two pentagons and one octagon, with no dangling bonds. Scanning tunneling spectroscopy measurements on divacancies generated in nearly ideal graphene show an electronic spectrum dominated by an empty-states resonance, which is ascribed to a nearly flat, spin-degenerated band of pi-electron nature. While the calculated electronic structure rules out the formation of a magnetic moment around the divacancy, the generation of an electronic resonance near the Fermi level reveals divacancies as key point defects for tuning electron transport properties in graphene systems.