▎ 摘　　要

In situ experiments for graphene nanoribbons (GNRs) under electron beam irradiation show their thinning process. In particular, carbon linear atomic chains (LACs) were observed with high resolution transmission electron microscopy. In order to further understand the structural evolution and breaking mechanisms under stress and a wide range of temperatures that are yet to be fully explored by experiments, we use a molecular dynamics (MD) method to simulate the mechanical properties of GNRs. At high temperatures, our simulations produce non-hexagons and long LACs, whose main features are similar to the experimental results. We show how defects lead to the formation of definitely stable LACs, while at low temperatures, tensile deformation modes become brittle due to localized defects, which are attributed to insufficient thermal energy. In the simulation of zigzag GNRs at high temperatures, we unexpectedly obtained a fracture of the armchair-zigzag bridge connected by non-hexagons. These results offer insights for nanoelectronic device fabrication through a stress-temperature-controlled procedure on GNRs. (C) 2011 American Institute of Physics. [doi:10.1063/1.3662183]