Nonlinear conductance reveals positions of carbon atoms in metallic single-wall carbon nanotubes

ArticleinPhysics of Condensed Matter 72(1):89-95 · November 2009with6 Reads
DOI: 10.1140/epjb/e2009-00303-4
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.
  • [Show abstract] [Hide abstract] ABSTRACT: By using a simple method, the effects of a substitutional magnetic impurity on the conductance of metallic single-wall carbon nanotubes, lying between two spin-polarized electron reservoirs, are studied. It is demonstrated how the differential conductance depends sensitively on the radius and length of nanotube as well as the position of impurity. It is shown that magnetic impurity produces more effect for the spin-polarized current between the antiparallel reservoirs than the parallel ones. (c) 2010 Elsevier B.V. All rights reserved.
    Full-text · Article · Nov 2010
  • [Show abstract] [Hide abstract] ABSTRACT: It has been recently shown [P. Partovi-Azar, A. Namiranian, J. Phys.: Condens. Matter, 24 (2012) 035301.] that Stone-Wales (SW) defects induce different electronic features when they are formed with different angels with respect to the axis of armchair carbon nanotubes. However, the electronic features introduced by SW defects in metallic zigzag and chiral carbon nanotubes is less considered in the literature. In this paper, by means of density functional calculations, we study the electronic effects induced by SW defects in metallic zigzag and chiral tubes. We inspect how these effects change with defect orientation and concentration. We show that two and three distinctive orientations of SW defects, respectively in the case of zigzag and chiral tubes, unlike those in armchair ones, behave the same and both introduce a semiconducting gap and an electron-rich region around the defects. For zigzag tubes, the longitudinal defects open wider band gaps than circumferential ones. The value of the gaps in zigzag and chiral tubes are attributed to the degree of deformation caused by the defects.
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