[SY-F9] Elastic field of lattice defects in low-dimensional nano-carbon materials
Carbon atoms build themselves into different materials such as fullerenes, diamond nano-thread, carbon nanotube (CNT), and graphene sheet (GS) in nanometer-scale. The materials are formally classified into point, line, and surface materials, which correspond to zero-, one- and two-dimensional materials, respectively. Many literatures report that the lattice defects affected mechanical properties and electronic properties. Lattice defects in such low-dimensional nano-carbon are limited into special atomic structures rather than bulk (three-dimensional) materials, but the properties of these low-dimensional materials depend on the lattice defects as well as bulk materials. Continuum theory, such as dislocation theory, has been developed sophisticatedly for very long years. In low-dimensional materials, however, theoretical approaches for lattice defects are just developing. In this study we discuss the elastic field of lattice defects in low-dimensional nano-carbon, e.g. Stone-Wales (SW) defects on single-walled carbon nanotubes (SWCNTs) and GS. The various equilibrium configurations of atomistic models with defects are obtained using LAMMPS. The site potential energy and stress distribution of each atom are evaluated in the vicinity of defects. We also measure a curvature and bond length to identify the out-of-plane deformation and in-plane deformation. We also study the dependence of elastic field on the chirality of CNT and the interaction of two SW defects in details. Formation energy significantly depends on chirality, i.e. diameter, of nanotube as well as the orientation and position of SW defect in SWCNT and GS. The results obtained for atomistic models are compared with an classical analytical solutions of plane stress which is established ideally with assumption of only in-of-plane deformation, and the effect of out-of-plane deformation of low-dimensional nano-carbon is discussed.