Abstract: Calculations have been made for the configurations of single-walled carbon nanotubes containing substitutional nitrogen impurity atoms with ab initio density functional theory. It has been found that N-doped zigzag single-walled carbon nanotubes are more stable than N-doped armchair carbon nanotubes. When more nitrogen atoms are incorporated into single-walled carbon nanotubes, the change of the structure along the tube longitude is greater than that along the tube axis. And we also have studied the bond structures for N-doped single-walled carbon nanotubes in detail.

Key words: carbon nanotube, nitrogen, doping