The deformation and failure behaviour of phosphorene nanoribbons under uniaxial tensile strain

We investigate the deformation and failure behavior of phosphorene nanoribbons (PNRs) with armchair (AC) and zigzag (ZZ) edges subjected to uniaxial tensile strain. It is found that the deformation and failure of PNRs are highly anisotropic. For ACPNRs, three stages were identified upon straining: the initial 'linear elastic' stage, which is closely related to the interactions between the adjacent nanoribbon puckers, followed by the 'bond rotation' stage, where the puckered structure of the phosphorene is flattened via bond rotation, and finally the 'bond stretching' stage, where the P-P bonds are strained up to the rupture limit. The failure is caused by the breaking of the most strained bonds, which are located in specific rows. For ZZ PNRs, however, the applied tensile strain leads to direct bond stretching and the final bond breakings are uniformly distributed across ZZ PNRs. It is also found that AC PNRs have a large failure strain (epsilon approximate to 0.5), but a low failure stress (sigma approximate to 50 GPa), whereas ZZ PNRs have a low failure strain (epsilon approximate to 0.1), but a high failure stress (sigma approximate to 100 GPa). For both AC and ZZ PNRs, their failure strain is insensitive while their failure stress is only moderately sensitive to the width.