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The electronic structure of the (9,0)–(18,0) double-walled zigzag carbon nanotubes in the presence of a uniform transverse electric field is studied by the tight-binding model. The electric field could induce the semiconductor–metal transition, change the direct gap into the indirect gap, alter the subband curvatures, destroy the double degeneracy, produce the new band-edge states, make more subbands...
Through the tight-binding model, the effect of electric field on electronic and optical properties of a zigzag (an armchair) H-terminated nanographite ribbon is studied. The effective electric field shifts the Fermi level (E F ), modifies the energy dispersions, alters the subband spacing, produces the new edge state, changes the band gap, and causes the semiconductor–metal transitions. First,...
The tight-binding model is employed to study magnetoelectronic structures of the AB-stacked graphite. A specifically full band calculation on overall energy region is presented to compare with SWMcC method, which only concerns the magnetoelectronic structures along the HKH-axis. It is found that magnetoband structures, strongly depending on the perpendicular magnetic field (B) and the interlayer interactions,...
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...
Magnetoelectronic states of carbon toroids have been studied within the tight-binding model. These states are mainly determined by the magnitude and the direction of the magnetic field, and the toroid geometry (chiral angle, height, and radius). The magnetic field can make the angular momentum (L) along the longitudinal direction undergo both a large shift and strong coupling. This effect leads to...
Optical excitations of finite carbon nanotubes by the cross polarized light are studied within the gradient approximation. They are dominated by the quantum size effects. The absorption spectra exhibit rich absorption peaks, mainly owing to many zero-dimensional discrete states. They strongly depend on the length, the radius, the chiral angles, and the magnetic flux. The absorption peaks gradually...
Magnetoelectronic structures of double-walled armchair carbon nanotubes are calculated according to the tight-binding model. Their features are dominated by the intertube interactions, the symmetric configurations, the magnetic flux, and the Zeeman splitting. The drastic changes of the low energy states, such as energy dispersion, wave function, and Fermi level, which also rely on the different symmetries,...
Magnetoelectronic structures of a two-dimensional (2D) graphite sheet are calculated by the tight-binding model. They are very sensitive to the magnitude of perpendicular magnetic field (B). B imposes the periodical boundary condition on the Bloch functions in the real and momentum spaces. Thus, B changes energy dispersions, energy spacing, bandwidth, and oscillation period of Landau levels. B could...
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