The effects of SiC-doped on the NMR parameters of the armchair and zigzag models of aluminum phosphide nanotubes: A DFT study

In this work the density functional theory (DFT) calculations are used to investigate the electrical properties of three SiC atoms doped on the representative (4, 4) armchair and (8, 0) zigzag aluminum phosphide nanotubes (AlPNTs). The mouths of nanotubes are capped by hydrogen atoms in order to saturate the dangling bonds of the boundaries and to simulate a longer tube and to decrease calculation time. The structures of all nanotubes were allowed to relax and the chemical shielding (CS) parameters were calculated for the atoms of optimized structures. The results indicated that the band gap energies and NMR parameters detect the effects of doping. The CS parameters also indicated that in both models of (4, 4) armchair and (8, 0) zigzag among all the P and Al atoms, which are directly connected to the Si and C atoms, have the smallest isotropic and anisotropic chemical shielding.