Molecular dynamics investigation of the mechanical properties of two different graphyne allotropes: alpha-graphyne and alpha(2)-graphyne

SN Jafari and Y Hakimi and S Rouhi, PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 119, 114022 (2020).

DOI: 10.1016/j.physe.2020.114022

Molecular dynamics simulations are used to study the mechanical properties of alpha-graphyne and alpha(2)-graphyne. The square and rectangular alpha-graphyne and alpha(2)-graphyne with different dimensions are modelled. It is seen that for both of the considered nanosheets, Young's modulus is smaller than along the armchair direction than along the zigzag direction. Similarly, zigzag alpha-graphyne has larger fracture strain than the armchair one. For the alpha(2) graphyne, however, the fracture strain along the armchair direction is larger than zigzag direction. Besides, it is observed that Young's modulus of the alpha-graphyne is smaller than alpha(2)-graphyne for both of the armchair and zigzag structures. However, the alpha-graphyne possesses larger fracture strain than alpha(2)-graphyne. It is also seen that Young's modulus of the square alpha-graphyne and alpha-graphyne nanosheet is not dependent on the nanosheet dimension. However, fracture strain and maximum stress of these nanosheets decrease by increasing the nanosheet size. Finally, the Poisson's ratio of the alpha-graphyne and alpha(2)-graphyne is obtained as large as 0.9 for some sizes.

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