Persistent currents in finite zigzag carbon nanotubes

Magnetic properties of finite zigzag carbon nanotubes are studied within the tight-binding model. The spin-B interaction (Zeeman splitting) causes the metal-semiconductor transition and thus produces a large persistent current (J) with special jump structures. This effect makes all zigzag carbon nanotubes exhibit a gigantic paramagnetism. It also destroys the periodicity of magnetic properties. The dependence on the magnetic flux, the length (w), the radius (r), the temperature (T), and the chirality (zigzag or armchair) is strong. The amplitude of J quickly decreases with increasing of (w, r, T). Zigzag carbon nanotubes differ significantly from armchair carbon nanotubes (or infinite zigzag carbon nanotubes) in features such as magnetic susceptibility and in special structures in J. (C) 2004 Elsevier Ltd. All rights reserved.