A new 2D auxetic CN2nanostructure with high energy density and mechanical strength

Qun Wei, Ying Yang, Alexander Gavrilov, Xihong Peng

Research output: Contribution to journalArticlepeer-review


The existence of a new two dimensional CN2structure was predicted usingab initiomolecular dynamics (AIMD) and density-functional theory calculations. It consists of tetragonal and hexagonal rings with C-N and N-N bonds arranged in a buckling plane, isostructural to the tetrahex-carbon allotrope. It is thermodynamically and kinetically stable suggested by its phonon spectrum and AIMD. This nanosheet has a high concentration of N and contains N-N single bonds with an energy density of 6.3 kJ g−1, indicating its potential applications as a high energy density material. It possesses exotic mechanical properties with a negative Poisson's ratio and an anisotropic Young's modulus. The modulus in the zigzag direction is predicted to be 340 N m−1, stiffer than those of h-BN and penta-CN2sheets and comparable to that of graphene. Its ideal strength of 28.8 N m−1outperforms that of penta-graphene. The material maintains phonon stability upon the application of uniaxial strain up to 10% (13%) in the zigzag (armchair) direction or biaxial strain up to 5%. It possesses a wide indirect HSE band gap of 4.57 eV, which is tunable between 3.37-4.57 eV through strain. Double-layered structures are also explored. Such unique properties may facilitate its potential applications as a high energy density material and in nanomechanics and electronics.

Original languageEnglish (US)
Pages (from-to)4353-4364
Number of pages12
JournalPhysical Chemistry Chemical Physics
Issue number7
StatePublished - Feb 21 2021

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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