Center for Opto-electronic Materials and Devices, Korea Institute of Science and Technology, Seoul 130-650, Korea.
Division of Electron Microscopic Research, Korea Basic Science Institute, Daejeon 305-333, Korea.
Sci Rep. 2016 Dec 21;6:39624. doi: 10.1038/srep39624.
Over the history of carbon, it is generally acknowledged that Bernal AB stacking of the sp carbon layers is the unique crystalline form of graphite. The universal graphite structure is synthesized at 2,600~3,000 °C and exhibits a micro-polycrystalline feature. In this paper, we provide evidence for a metastable form of graphite with an AA' structure. The non-Bernal AA' allotrope of graphite is synthesized by the thermal- and plasma-treatment of graphene nanopowders at ~1,500 °C. The formation of AA' bilayer graphene nuclei facilitates the preferred texture growth and results in single-crystal AA' graphite in the form of nanoribbons (1D) or microplates (2D) of a few nm in thickness. Kinetically controlled AA' graphite exhibits unique nano- and single-crystalline feature and shows quasi-linear behavior near the K-point of the electronic band structure resulting in anomalous optical and acoustic phonon behavior.
在碳的历史中，人们普遍认为 sp 碳层的 Bernal AB 堆叠是石墨的独特结晶形式。通用的石墨结构是在 26003000°C 下合成的，具有微多晶特征。本文提供了具有 AA'结构的石墨亚稳形式的证据。通过在1500°C 下对石墨烯纳米粉末进行热等离子体处理，可以合成非 Bernal AA'石墨同素异形体。AA'双层石墨烯核的形成有利于优先纹理生长，并导致单晶 AA'石墨以纳米带（1D）或微板（2D）的形式存在，厚度为数纳米。动力学控制的 AA'石墨具有独特的纳米和单晶特征，并在电子能带结构的 K 点附近表现出准线性行为，导致异常的光学和声学声子行为。
