Phagraphene: A Low-Energy Graphene Allotrope Composed of 5–6–7 Carbon Rings with Distorted Dirac Cones

Using systematic evolutionary structure searching we propose a new carbon allotrope, phagraphene [fæ'græfi:n], standing for penta-hexa-hepta-graphene, because the structure is composed of 5-6-7 carbon rings. This two-dimensional (2D) carbon structure is lower in energy than most of the predicted 2D carbon allotropes due to its sp(2)-binding features and density of atomic packing comparable to graphene. More interestingly, the electronic structure of phagraphene has distorted Dirac cones. The direction-dependent cones are further proved to be robust against external strain with tunable Fermi velocities.

• SU
  State University of New York

  Award: 4E NoE
• NN
  National Natural Science Foundation of China

  Awards: 91221101, 11174152
• MO
  Ministry of Education of the People's Republic of China

  Award: 65121009
• MO
  Ministry of Science and Technology of the People's Republic of China

  Awards: 2012CB932302, 2012CB921900
• CS
  China Scholarship Council

  Award: 201408320093
• NS
  Natural Science Foundation of Jiangsu Province

  Award: BK20130859
• DA
  Defense Advanced Research Projects Agency

  Awards: W31P4Q1310005, W31P4Q1210008
• PF
  Program for New Century Excellent Talents in University

  Award: NCET-12-0278
• DO
  Division of Materials Research

  Award: DMR-1231586
• DO
  Division of Earth Sciences

  Award: EAR-1114313