Electric and magnetic field effects on electronic structure of straight and toroidal carbon nanotubes

Abstract

Nanotubes have been proved as promising candidates for many technological applications in the nanoscale word and different physical properties have been studied and measured along the few recent years. Here we investigate the role played by external magnetic and electric fields on the electronic properties of toroidal and cylindrical straight carbon nanotubes. A single-π band tight-binding Hamiltonian is used and two types of model-calculations are adopted: real-space renormalization techniques, based on Green function formalism, and straight diagonalization calculation. Both electric and magnetic fields may be properly applied, in different configurations, to modify the energy spectra and transport properties, providing metal-insulator transitions for particular tube geometries.

Electric Field Quenching of Carbon Nanotube Photoluminescence

“…The importance of such interactions has led several theoretical researchers to investigate the electronic and optical properties of metallic and semiconducting carbon nanotubes in external electric and magnetic fields. [13][14][15][16][17] It was predicted that applying a transverse electric field to semiconducting SWCNTs will induce changes in band gaps and affect the lifetime of electronically excited states. 13,14,16 It has also been pointed out that applied electric fields should shift the positions of optical absorption peaks and increase their number by breaking state degeneracy.…”

“…There is a continuing search for other applications arising from the interaction of applied fields with carbon nanotubes. The importance of such interactions has led several theoretical researchers to investigate the electronic and optical properties of metallic and semiconducting carbon nanotubes in external electric and magnetic fields. – It was predicted that applying a transverse electric field to semiconducting SWCNTs will induce changes in band gaps and affect the lifetime of electronically excited states. ,, It has also been pointed out that applied electric fields should shift the positions of optical absorption peaks and increase their number by breaking state degeneracy. Recent electroabsorption studies have detected very small (∼10 −4 ) relative changes in SWCNT absorption in high electric fields (0.1−1 MV/cm). , However, experimental studies of SWCNT excited states in external fields remain very limited.…”

Strong Variation of Electronic Properties of MoS2 and WS2 Nanotubes in the Presence of External Electric Fields

“…Albeit the interesting properties of TMDC-NTs, studies of their applications in the field of electronics remain insufficient in contrast to their layered 2D counterparts, which have been intensively explored in recent years. − Of particular interest, the effect of external electric field yields significant modifications on the electronic and optical properties of 2D TMDCs. − Similar findings are also shown for some nanotubular materials, including carbon NTs, − boron-nitride NTs, , and zinc-oxide NTs . However, the effect of the applied electric field on the properties of TMDC-NTs is still a subject to be addressed.…”

Effect of magnetic field on electrical properties of nanocrystalline poly(vinylidene fluoride) samples

“…The modifications registered depend on the treatment conditions, e.g. on the magnetic field intensity and the number of intersected magnetic poles having opposite polarity, and also on the paramagnetic properties of the solution subjected to magnetization 1–6…”