Band Gap Mechanism for Armchair Single Walled Carbon Nanotubes and Metal Semiconductor Transition for Symmetry Breaking

Abstract

We have studied structures of single walled carbon nanotubes and metalsemiconductor transition for the symmetric breaking. It was found that band gapexisted for metallic armchair single walled carbon nanotubes. Calculations were madeto analyse the meta-stability of the corrugated structures of armchair single walledcarbon nanotubes. The corrugated single walled carbon nanotube structures are alwayslower in energy than the non corrugated nanotubes. The curvature effect was that thecorrugated structure breaks the local symmetry between different carbon atoms. A truegap is created which does not vanish even when an external magnetic field is swept.The corrugation length and band gap gaps are decaying functions of the nanotubesradius and approached zero for carbon nanotube such as graphene. This was also truefor zigzag and chiral single wall carbon nanotubes. The obtained results were found ingood agreement with previously obtained results