Mechanical and Electrical Properties of Single Walled Carbon Nanotubes: A Computational Study

Over the recent years, numerical modelling and computer based simulation of the properties of carbon nanotubes have become the focal points of research in computational nano-science. In this paper, we present the computational studies about the mechanical and transport properties of armchair (4, 4) and zigzag (4, 0) single walled carbon nanotubes (SWCNT). Unlike other materials, carbon nanotubes are so small that changes in structure can affect the Young’s modulus. Young's modulus for an armchair single-wall carbon nanotube and zigzag single-wall carbon nanotube are calculated using an atomistic approach and density functional theory (DFT). Atomic forces and total energies for strained carbon nanotube segments are computed using Atomistix's Virtual NanoLab (VNL) and ToolKit (ATK) software. For a maximum strain of one percent, elastic moduli are calculated using both force-strain and energy-strain data. The average values found for Young's modulus are in the range 1.8 to 4.17 TPa depending on the cross-sectional area taken for the carbon nanotube and the calculation method used. This is in good agreement with recent experimental findings. By using ab initio density functional theory (DFT) and non-equilibrium green function approach (NEGF), the structural and electronic properties such as electronic band structure, density of states (DOS) and transmission spectrum of the single walled carbon nanotube (SWCNT) are investigated. The results suggest a wide range for practical applications, such as NEMS, acoustic sensors and nano actuators.