The influence mechanism of the nano-cutting direction on the edge atomic arrangement characteristics of graphene nanoribbons

This study uses molecular dynamics simulation to reveal the processing mechanism of diamond probe nano cutting of single-layer graphene at the atomic scale, focusing on the relationship between cutting direction and the regularity and structural integrity of graphene nanoribbons. The results show that the stress is uniform in the initial stage, the critical stage has concentrated stress at the contact point, and in the fracture stage, there is a coexistence of stress release and accumulation in some areas, forming a gradient stress field (including high stress areas, compression areas, and elastic fields). The stress distribution of [100] and [010] crystal orientations is consistent, which is prone to edge reconstruction defects and elastic bonding. The crystal orientation does not affect the number of broken bonds. The cutting force amplitudes are similar for different crystal orientations, but the uniformity is different. The Fx fluctuation is small for the [010] crystal orientation, and Fz is more stable for the [100] crystal orientation. The potential energy is mainly converted into elastic deformation energy, and there is no significant difference in the potential energy and temperature distribution between the [100] and [010] crystal orientations. The oscillation of the potential energy curve is due to the periodic deformation of the lattice and atomic reconstruction. The temperature is higher in the contact area with the probe due to the preferential absorption of kinetic energy. Cutting along the [010] crystal orientation leads to more significant disorder in the structure, with severe damage to the sp² network, while the [100] crystal orientation has fewer defects and is more suitable for preparing high-quality nanoribbons. The "crystal orientation -stress -defect" correlation model established in this study will provide a theoretical basis for the preparation of graphene nanodevices with specific edge quality.