5 research outputs found
Thermal Stability of Metallic Single-Walled Carbon Nanotubes: An O(N) Tight-Binding Molecular Dynamics Simulation Study
Order(N) Tight-Binding Molecular Dynamics (TBMD) simulations are performed to
investigate the thermal stability of (10,10) metallic Single-Walled Carbon
Nanotubes (SWCNT). Periodic boundary conditions (PBC) are applied in axial
direction. Velocity Verlet algorithm along with the canonical ensemble
molecular dynamics (NVT) is used to simulate the tubes at the targeted
temperatures. The effects of slow and rapid temperature increases on the
physical characteristics, structural stability and the energetics of the tube
are investigated and compared. Simulations are carried out starting from room
temperature and the temperature is raised in steps of 300K. Stability of the
simulated metallic SWCNT is examined at each step before it is heated to higher
temperatures. First indication of structural deformation is observed at 600K.
For higher heat treatments the deformations are more pronounced and the bond
breaking temperature is reached around 2500K. Gradual (slow) heating and
thermal equilibrium (fast heating) methods give the value of radial thermal
expansion coefficient in the temperature range between 300K-600K as
0.31x10^{-5}(1/K) and 0.089x10^{-5}(1/K), respectively. After 600K, both
methods give the same value of 0.089x10^{-5}(1/K). The ratio of the total
energy per atom with respect to temperature is found to be 3x10^{-4} eV/K