Theoretical study of electronic density of states for carbon nanotubules

The electronic density of states (DOS) has been calculated for carbon nanotubules with various radius within the tight-binding approximation. The objective of the present study is to provide useful information on the valence band for an experimental research which will be possible in the near future. Some distinctive features are found in the DOS of tubules with small radii and that of (2n, 0) tubules. In particular for (2n, 0) tubules a δ-like peak due to a flat band always appears at the same energy irrespective of a tubule radius (R). From a simple consideration, it is found that its intensity varies as 1/R depending on R.