Highly Anisotropic Dirac Fermions in Square Graphynes.

نویسندگان

  • L Z Zhang
  • Z F Wang
  • Zhiming M Wang
  • S X Du
  • H-J Gao
  • Feng Liu
چکیده

We predict a family of 2D carbon (C) allotropes, square graphynes (S-graphynes) that exhibit highly anisotropic Dirac fermions, using first-principle calculations within density functional theory. They have a square unit-cell containing two sizes of square C rings. The equal-energy contour of their 3D band structure shows a crescent shape, and the Dirac crescent has varying Fermi velocities from 0.6 × 10(5) to 7.2 × 10(5) m/s along different k directions. Near the Fermi level, the Dirac crescent can be nicely expressed by an extended 2D Dirac model Hamiltonian. Furthermore, tight-binding band fitting reveals that the Dirac crescent originates from the next-nearest-neighbor interactions between C atoms. S-graphynes may be used to build new 2D electronic devices taking advantages of their highly directional charge transport.

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عنوان ژورنال:
  • The journal of physical chemistry letters

دوره 6 15  شماره 

صفحات  -

تاریخ انتشار 2015