Curvature and external electric field effects on the persistent current in chiral toroidal carbon nanotubes
Department of Physics & Institute for Nanophysics and Rare-earth Luminescence, Xiangtan University, Xiangtan, 411105, Hunan, P.R. China
Revised: 9 December 2008
Published online: 9 January 2009
Taking into account the intrinsic curvature, we calculate the persistent currents (Ipcs) in chiral toroidal carbon nanotubes (TCNs) by developing the supercell approach. It is shown that in the presence of curvature, the typical current (Ity) oscillates with the unit cell number (P) and tends to be zero, while it damps exponentially in the absence of curvature. Due to the curvature effects, especially, a paramagnetism-diamagnetism transition is observed in chiral TCNs, depending on the ring diameter and chirality. In addition, the effect of external electric field energy (Eef) on persistent current is also explored. It is shown that in the presence of electric field, Ity vary unmonotonously with Eef. A pronounced peak of Ity is obtained at high Eef region. By modulating the value of Eef, a paramagnetism-diamagnetism or diamagnetism- paramagnetism transition is observed.
PACS: 73.23.Ra – Persistent currents / 73.22.-f – Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009