Exploring the electronic and magnetic properties of zigzag and armchair BC2N nanotubes: a DFT study

A density functional study is performed to investigate the electronic and magnetic properties of zigzag and armchair BC2N nanotubes based on the C-13, N-15, and B-11 NMR parameters and natural charge analysis. We considered three types of zigzag nanotubes, ZZ-1, ZZ-2, and ZZ-3 (n, 0) with n = 3, 4, and 5, as well as two types of armchair nanotubes: AC-1 and AC-2 (n, n) with n = 3 and 4. The obtained results indicate the divisions of the electrostatic environments around C nuclei into a few layers, consistent with the calculated natural charges on C atoms. A good correlation is seen between the layers of chemical shielding isotropy as well as anisotropy, sigma (iso), and Delta sigma, and the five local structures around carbon atoms. Successive BN units lead to larger N-15 sigma (iso) values (96.5-105.5 ppm) in comparison with the individual BN units (74.3-92.0 ppm in the ZZ-2(n, 0) and 47.4-61.7 ppm in the ZZ-3(n, 0)). Slight differences in the values of B-11 sigma (iso) clarify diminutive diversity in the electron densities of boron nuclei, while Delta sigma values indicate the more apparent range of changes.