• 文献标题:   Symmetry breaking and low energy conformational fluctuations in amorphous graphene
  • 文献类型:   Article
  • 作  者:   LI Y, DRABOLD DA
  • 作者关键词:   amorphous graphene, lowenergy excitation, symmetry breaking, vibrational mode
  • 出版物名称:   PHYSICA STATUS SOLIDI BBASIC SOLID STATE PHYSICS
  • ISSN:   0370-1972
  • 通讯作者地址:   Ohio Univ
  • 被引频次:   11
  • DOI:   10.1002/pssb.201248481
  • 出版年:   2013

▎ 摘  要

Recently, the prospects for amorphous phases of graphene (-g) have been explored computationally. Initial models were flat, and contained odd-member rings, while maintaining threefold coordination and sp2 bonding. Upon relaxation, puckering occurs, and may be traced to the existence of pentagons, in analogy with the situation for fullerenes. In this work, we systematically explore the inherent structures with energy close to the flat starting structure. As expected, the planar symmetry can be broken in various ways, which we characterize for 800-atom model of -g, always using local basis density functional techniques. The classical normal modes of various structural models are discussed, with an emphasis on imaginary modes indicating the evolution from flat to puckered. We also discuss very low energy conformational fluctuations akin to those seen previously in amorphous silicon, and reflect on the nature of the amorphous ground state within a network of fixed topology. For completeness, high energy modes were also computed, and are found to be associated with strained parts of the network.