Using density-functional theory (DFT) methods, we investigate structural, electronic, and transport properties of step-kinked single-walled carbon nanotubes (SWCNT). To devise a sensible model for the joint section of the kinked nanotube, we examine relative stability of two (6,0) carbon-nanotube- based C672 isomers, namely, a carbon nanoring and a carbon hexagonal nanotorus. We find that the hexagonal nanotorus C672 is energetically more favorable than the isomeric nanoring (i.e., circular nanotorus) C 672. By use of the kinked section of the hexagonal nanotorus as a model joint, the periodic step-kinked carbon nanotubes can be built. According to the DFT calculation using the hybrid B3LYP functional, we find that introduction of the periodic kinks turns the perfect (5,0) SWCNT with zero band gap (J. Phys. Chem. Lett. 2010, 1, 2946) into a semiconductor with a band gap ∼0.76 eV. In contrast, the step-kinked (6,0) SWCNT is still a metal with zero band gap, like the perfect (6,0) SWCNT. We also compare the electronic transport properties of a perfect (5,0) SWCNT with the step-kinked (5,0) SWCNT. The former has a nonzero steplike electron transmission distribution near the Fermi level, while the latter shows some sharp transmission peaks around the Fermi level.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films