Uniaxial-stress effects on the electronic properties of carbon nanotubes

Using a semiempirical tight-binding approach modified through introduction of a deformation potential, we have calculated the effects of uniaxial stress on the electronic density of states of carbon tubules. For zigzag tubules (n,0) the gap varies linearly with stress and independently of diameter: |${\mathrm{dE}}_{\mathrm{gap}}$/dσ|=10.7 meV/GPa for |σ| ≺10 GPa, and a semiconductor to metal transition is predicted. The behavior is strongly dependent on whether n=3q,3q-1,3q+1. The armchair tubules remain metallic under all conditions studied.