Nonlinear conductance reveals positions of carbon atoms in metallic single-wall carbon nanotubes
ABSTRACT Nonlinear quantum conductance in finite metallic single-wall carbon nanotubes due to presence of a single defect has been
studied theoretically using π-orbital tight-binding model. The correction to the conductance induced by defects is sensitively
dependent on wavefunction amplitudes of contributing electronic states. It has been shown that by calculating this correction
to the first order, we can delineate the position of carbon atoms on tubular surface. It can also be used to specify the SWCNT
at hand and its level spacing.
- Phil. Mag. 01/1970;
Article: Carbon nanotube quantum resistors[show abstract] [hide abstract]
ABSTRACT: The conductance of multiwalled carbon nanotubes (MWNTs) was found to be quantized. The experimental method involved measuring the conductance of nanotubes by replacing the tip of a scanning probe microscope with a nanotube fiber, which could be lowered into a liquid metal to establish a gentle electrical contact with a nanotube at the tip of the fiber. The conductance of arc-produced MWNTs is one unit of the conductance quantum G0 = 2e2/h = (12.9 kilohms)-1. The nanotubes conduct current ballistically and do not dissipate heat. The nanotubes, which are typically 15 nanometers wide and 4 micrometers long, are several orders of magnitude greater in size and stability than other typical room-temperature quantum conductors. Extremely high stable current densities, J > 10(7) amperes per square centimeter, have been attained.Science 07/1998; 280(5370):1744-6. · 31.20 Impact Factor
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ABSTRACT: Despite the potential impact that carbon nanotubes and their composites would have in many areas of science and industry, very little is known about their microscopic strength or their behavior under mechanical load. We have investigated the static and dynamical properties of carbon nanotubes under uniaxial tension, using both massively parallel first-principles methods and classical many body potentials. The simulations have led to an identification of the first stages of the mechanical yield of carbon nanotubes. Beyond a critical value of the tension, the system releases its excess strain via formation of topological defects. In strained nanotubes at high temperatures we observe the spontaneous formation of double pentagon-heptagon defect pairs. Tubes containing these defects are energetically preferred to uniformly stretched tubes at strains greater than 5%. These topological defects act as nucleation centers for the formation of dislocations in the originally ideal graphite network, and they constitute the onset of a plastic deformation of the carbon nanotube. The mechanism of formation of such defects, their energetics and transformations will be described.Physical Review B. 01/1998; 57(8):4277-4280.