Nanotube zone folding
= Nanotube zone folding
An approximation that samples the <graphene> bands on wave vectors satisfying $\mathbf k\cdot\mathbf C_h=2\pi\ell$, where $\mathbf C_h$ is the <carbon nanotube chiral vector>. It produces one-dimensional subbands and the ideal metallicity criterion $n-m\equiv0\pmod3$; curvature and interactions can modify its predictions.