Electronic and mechanical properties of (6,1) single-walled carbon nanotubes with different tube diameters: a theoretical study

We investigated the electronic and mechanical properties of single-walled carbon nanotubes (SWCNTs) with different tube diameters using density functional theory (DFT) and molecular dynamics (MD) simulation, respectively. The carbon nanotubes' electronic properties were derived from the index number (n(1), n(2)), lattice vectors, and the rolled graphene sheet orientation. For (6,1) SWCNT, (n(1)-n(2))/3 is non-integer, so the expected characteristic is semiconducting. We have considered (6,1) Chiral SWCNT with different diameters 'd' (4.68 angstrom, 4.90 angstrom, 5.14 angstrom, 5.32 angstrom, 5.53 angstrom) corresponds to respective bond lengths 'delta' (1.32 angstrom, 1.38 angstrom, 1.45 angstrom, 1.50 angstrom and 1.56 angstrom) and then analyze the electronic properties from the Linear Combination of Atomic Orbitals (LCAO) based on DFT. We have used both the DFT-1/2 and GGA exchange energy correlation approximations for our calculation and compared the results. In both cases, the energy bandgap is decreasing order with the increase in bond lengths. The lowest value of formation energy was obtained at the bond length delta = 1.45 angstrom (d = 5.14 angstrom). For the mechanical properties, we have calculated Young's modulus using molecular dynamics (MD) simulations. From our calculation, we have found that the (6,1) SWCNT with bond length 1.45 angstrom (d = 5.14 angstrom) has Young's modulus value of 1.553 TPa.

Automated summary

Through density functional theory (DFT) and molecular dynamics (MD) simulations, we investigated the electronic and mechanical properties of single-walled carbon nanotubes (SWCNTs) with different diameters. Our results show that as the bond length increases, the energy bandgap decreases, with the lowest formation energy obtained at a specific bond length. Moreover, by calculating Young's modulus, we found that a specific bond length exhibited the highest value.