Comprehensive first-principles calculations are performed on diverse arrangements of relevant chemical defects in fluorographene to provide accurate microscopic insights into the process of graphene fluorination. The minimum energy paths for the half- and full-fluorination processes are calculated for a better understanding of these phenomena. While experimental observations indicate a much slower rate of the full-fluorination process, compared with the half-fluorination one, the obtained energy profiles demonstrate much enhanced fluorine adsorption after the half-fluorination stage. This ambiguity is explained in terms of significant chemical activation of the graphene sheet after half-fluorination, which remarkably facilitates the formation of chemical contaminants in the system and thus substantially slows down the full-fluorination procedure. After considering the binding energy and durability of the relevant chemical species, including hydrogen, oxygen, and nitrogen molecules and xenon atom, it is argued that oxygen-fluorine ligands are the most likely chemical contaminants opposing the full-fluorination of a graphene sheet. We propose an oxygen desorption mechanism for the atomic description of the full-fluorination procedure in realistic situations. It is argued that the proposed mechanism explains well much enhanced rate of the full-fluorination procedure at elevated temperatures.
Reversible Fluorination of Graphene: towards a Two-Dimensional Wide Bandgap Semiconductor
我们报告了石墨烯氟化物的合成和证据，石墨烯是一种二维宽带隙半导体。氟化石墨烯表现出六方晶序和强绝缘行为，在室温下电阻超过10 G $Ω$。氟化石墨烯中的电子输运通过由于带隙中的局域态的存在而在二维中的可变范围跳跃来很好地描述。通过还原氟化石墨烯获得的石墨烯是高度导电的，在室温下表现出小于100 k $Ω$的电阻率。我们的方法提供了一种新的途径，可逆工程的能带结构和导电性的石墨烯的电子和光学应用。
Holonomic quantum computation on graphene from Atiyah-Singer index theorem
Centro de Ciências, Tecnologia e Saúde, Universidade Estadual da Paraíba（帕拉伊巴州立大学科学与技术健康科学中心）；Unidade Acadêmica de Física, Universidade Federal de Campina Grande（坎皮纳格兰德联邦大学物理学术单位）；Instituto de Física, Universidade Federal de Alagoas（阿拉戈阿斯联邦大学物理研究所）；Departamento de Física, Universidade Federal da Paraíba（帕拉伊巴联邦大学物理系）
