A new 2D auxetic CN₂ nanostructure with high energy density and mechanical strength

The existence of a new two dimensional CN2 structure was predicted using ab-initio molecular dynamics (AIMD) and density-functional theory calculations. It consists tetragonal hexagonal rings with C-N N-N bonds arranged in buckling plane, isostructural to tetrahex-carbon allotrope. is thermodynamically kinetically stable suggested by its phonon spectrum AIMD. This nanosheet has high concentration N contains single an energy density 6.3 kJ/g, indicating potential applications as materials. possesses exotic mechanical properties negative Poisson's ratio anisotropic Young's modulus. modulus the zigzag direction be 340 N/m, stiffer than h-BN penta-CN2 sheets comparable graphene. Its ideal strength 28.8 N/m outperforms that penta-graphene. material maintains stability upon application uniaxial strain up 10% (13%) (armchair) or biaxial 5%. wide indirect HSE band gap 4.57 eV which tunable between 3.37 - through strain. Double-layer structures are also explored. Such unique may have materials, nanomechanics electronics.