Spectroscopic Properties and STM Images of Carbon Nanotubes

Abstract

We present a theoretical study of the role of the local environment in the electronic properties of carbon nanotubes: isolated single- and multi-wall nanotubes, nanotube-ropes, tubes supported on gold and cutted to finite length. Interaction with the substrate or with other tubes does not alter the scanning-tunneling-microscopy (STM) patterns observed for isolated tubes. STM-topographic images of topological defects (pentagon/heptagon pair) and tube-caps have also been studied. In both cases the obtained image depends on the sign of the applied voltage and it can be described in terms of the previous catalog of STM-images (interference between electronic waves scattered by the defect). We also have computed the electronic density of states for isolated tubes with different chiralities and radii confirming a correlation between the peak-structure in the DOS and the nanotube diameter, however the metallic plateau in the DOS also depends on the nanotube chirality. Furthermore, the conduction and valence band structures are not fully symmetrical to one another. In contrast to STM images, the interaction with the substrate does modify the energy levels of the nanotube. We observe opening of small pseudogaps around the Fermi level and broadening of the sharp van Hove singularities of the isolated single-walled-nanotubes that can be used to extract useful information about the tube structure and bonding. The combination of STM and spectroscopic studies opens a new technique to address the electronic and structural properties of carbon and composite nanotubes.

arXiv comment9 pages, 8 eps figures. Applied Physics A (in press)

Cited by in corpus (8)

• Electronic and optical properties of graphene nanoribbons in external fields
• Optical absorption and electron energy loss spectra of carbon and boron nitride nanotubes: a first principles approach
• Electronic and Structural Properties of Carbon Nano-Horns
• Electronic structure of polychiral carbon nanotubes
• Carbon Nanotubes Band Assignation, Topology, Bloch States and Selection Rules
• Defect-induced multicomponent electron scattering in single-walled carbon nanotubes
• Geometry-induced smoothing of van Hove singularities in capped carbon nanotubes
• Transport through the intertube link between two parallel carbon nanotubes