Bending Deformation on the electronic structure of the (3,3), (4,4), (5,0) and (6,0) single-wall carbon nanotubes

In this work we investigate the effect of bending defect on the electronic and structural properties of the (3,3), (4,4), (5,0) and (6,0) single-wall carbon nanotubes (SWCNTs) using density functional theory (DFT) within Becke three parameter Lee–Yang–Parr (B3LYP) functional using 6-31 basis set. Our result revealed that as the bending angle increases, the deformation of atomic structure of the tube increases, particularly in the centralized zone of the tube. The obtained outcomes revealed that the bandgap fluctuates with the bending angle of CNTs and the cohesive energy, the highest occupied (E_HOMO) and the lowest unoccupied molecular orbitals energies (E_LUMO) decrease (in magnitude) as the CNTs bending increases. On the other hand, the electron affinity and the ionization potential increases with the bending angle of CNTs, while the Fermi energy decreases with the bending angle of CNTs, with a fluctuation of Fermi energy with the bending for (4,4) tube. Finally, in the presence of bending deformation, the highest number of density of states in the valence and conduction bands decrease with increasing the bending angle of CNTs.