Mechanical property enhancement of one-dimensional nanostructures through defect-mediated strain engineering

Abstract

The presence of defects is assumed to deteriorate mechanical properties, which has led to immense focus on fabricating perfect nanostructures. Herein, we prove that inherent defects can be employed to enhance the mechanical characteristics of low-dimensional materials via the molecular dynamics (MD) technique: defective nanobelts (NBs) are found to have higher critical stress and Young’s modulus compared with their perfect counterparts — up to 63% and 26%, respectively. Such an improvement has already been observed in nanowires (NWs), and can be justified by the interaction between localized Stacking fault (SF)-induced stress and surface stress. Additionally, twin boundary formation was observed to occur as an alternative stress relaxation mechanism in high densities of SFs, which delays wurtzite to hexagonal phase transition and further gives rise to structural toughness by forming a plateau in the stress–strain curve. Further, a systematic study was performed to investigate the effect of various design parameters, e.g., size, aspect ratio, and random distribution, on the mechanical response of the defective NBs.