Strain Induced Insulator–Metal Transition in Single WallCarbon Nanotubes

Abstract

In terms of a single-π orbital model, an analytical expression of thelowest-lying conduction-band and the highest-lying valence-band is derivedfor single wall carbon nanotubes under both the uniaxial and torsionalstrains. We observe not only semiconductor–metal transitions in primarymetallic tubes, but also insulator–metal transitions in semiconductingtubes. Additionally, an indirect transition of electrons and a quantizedelectron-resonance have been expected in optical spectrum experiments of thenanotubes.