Erratum: Radial oscillations of local density of states in carbon nanotubes [Phys. Rev. B<b>63</b>, 245111 (2001)]

Ferreira, M. S.; Dargam, T. G.; Muniz, R. B.; Latgé, A.

doi:10.1103/physrevb.65.039901

Cited by 10 publications

(13 citation statements)

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“…From Fig. (6) we see that ρ(ε) has an absolute maximum at ε = 1 eV, which is reminiscent of the Van Hove singularity in the graphite sheet, and exhibits well-defined oscillations as a function of the nanotube radius [39]. On the other hand, g(ε) is peaked at ε = εF .…”

Section: B Extrapolation To Large Lmentioning

confidence: 87%

W=0pairing in(N,N)carbon nanotubes away from half filling

2002

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We use the Hubbard Hamiltonian H on the honeycomb lattice to represent the valence bands of carbon single-wall (N, N ) nanotubes. A detailed symmetry analysis shows that the model allows W = 0 pairs which we define as two-body singlet eigenstates of H with vanishing on-site repulsion. By means of a non-perturbative canonical transformation we calculate the effective interaction between the electrons of a W = 0 pair added to the interacting ground state. We show that the dressed W = 0 pair is a bound state for resonable parameter values away from half filling. Exact diagonalization results for the (1,1) nanotube confirm the expectations. For (N, N ) nanotubes of length l, the binding energy of the pair depends strongly on the filling and decreases towards a small but nonzero value as l → ∞. We observe the existence of an optimal doping when the number of electrons per C atom is in the range 1.2÷1.3, and the binding energy is of the order of 0.1 ÷ 1 meV.

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Section: B Extrapolation To Large Lmentioning

confidence: 87%

W=0pairing in(N,N)carbon nanotubes away from half filling

2002

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“…In order to minimize the number of free parameters the nearest neighbor hopping integral is kept constant in the entire device. As regards the inter-tube interaction we treat the hopping integral as a free parameter of the order of t int ∼ t/10 (as for the interlayer distance in graphite 19 ), although in general t int depends exponentially on distance and also on angles between the π orbitals of the involved atoms. 20 It should be also admitted that another complexity, not captured by our simple structural model (two armchair tubes), is a possible additional off-diagonal disorder due to incommensurability between shells (cf.…”

Section: Formalismmentioning

confidence: 99%

Giant magnetoresistance of multiwall carbon nanotubes: Modeling the tube/ferromagnetic-electrode burying contact

Krompiewski

Gutiérrez

2004

Phys. Rev. B

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We report on the giant magnetoresistance (GMR) of multiwall carbon nanotubes with ultra small diameters. In particular, we consider the effect of the inter-wall interactions and the lead/nanotube coupling. Comparative studies have been performed to show that in the case when all walls are well coupled to the electrodes, the so-called inverse GMR can appear. The tendency towards a negative GMR depends on the inter-wall interaction and on the nanotube length. If, however, the inner nanotubes are out of contact with one of the electrodes, the GMR remains positive even for relatively strong inter-wall interactions regardless of the outer nanotube length. These results shed additional light on recently reported experimental data, where an inverse GMR was found in some multiwall carbon nanotube samples.

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“…We adopt a tight-binding Hamiltonian and follow the single-particle Green's function formalism to obtain LDOS within real-space renormalization techniques [3,6]. Taking into account that electron transport on the molecular scale became a topic of intense and relevant applications, phys.…”

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confidence: 99%

“…[3], here we investigate the nature and spatial localization of the bound states of S/S/S and S/M/S QDs. We adopt a tight-binding Hamiltonian and follow the single-particle Green's function formalism to obtain LDOS within real-space renormalization techniques [3,6]. Taking into account that electron transport on the molecular scale became a topic of intense and relevant applications, we also study the conductance of quantum dots modelled as M/M/M CNs, adopting the Landauer-Kubo formalism [7].…”

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confidence: 99%

Carbon Nanotube Quantum Dots

Rocha

Dargam

Latgé

2002

phys. stat. sol. (b)

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PACS: 71.20.Tx; 73.21.La; 73.63.Kv We present a theoretical study of the local electronic properties of quantum-dot nanotubes composed of different isolated nanotubes joined via modelled junctions (defect pairs composed of heptagon and pentagon along the axial direction of pure nanotubes). The heterostructures are studied following a single p-band tight-binding Hamiltonian and adopting real-space renormalization techniques within the Green's function formalism. The conductance of semiconducting and metallic dots is analysed as a function of the dot sizes for energies close to the Fermi level. Different transport regimes are found depending upon the electronic nature of the dot and also on the contacts.Carbon nanotubes (CNs) are cylindrical molecules which are attracting much attention since their discovery in 1991 [1]. A single-wall CN may be described by a graphene sheet rolled up and determined by a chiral vector, C h ¼ na 1 þ ma 2 ðn; mÞ, with a ð1; 2Þ being unit vectors of a graphene lattice. They present unique physical properties due to the electronic confinement along the circumferential direction, assuming metallic or semiconducting behaviour depending only on their particular geometry such as diameter and chirality [2]. However, their electronic character may be changed, for instance, by introducing topological defects in the hexagonal bond network. In this sense, an intramolecular junction can be produced through a 5-7 defect pair (pentagon-hexagon) in order to connect two segments of tubes with different chirality and diameters. These tubular heterostructures offer news perspectives for nanoelectronic technology.Recently, a detailed study of local electronic properties on CN heterojunctions (metal-semiconductor) was addressed [3] by investigating how the local density of states (LDOS) changes from the metallic to the semiconducting side. Based on a simple picture, the authors have shown that the electronic properties of the connected system are related to the bulk electronic structure of the pure CNs, being independent of the junction.Transport measurements performed in single-wall carbon nanotubes deposited on metallic contacts [4] have shown evidences of resonant tunnelling through quantized energy levels. Such reports stimulated several theoretical models of carbon nanotube quantum dots (QDs). Particularly, a semiconductor/metal/semiconductor (S/M/S) heterostructure was proposed by Chico et al. [5], who showed that this system behaves as an ideal zero-dimensional device, presenting completely confined electronic states.Following the same picture used in Ref.[3], here we investigate the nature and spatial localization of the bound states of S/S/S and S/M/S QDs. We adopt a tight-binding Hamiltonian and follow the single-particle Green's function formalism to obtain LDOS within real-space renormalization techniques [3,6]. Taking into account that electron transport on the molecular scale became a topic of intense and relevant applications, phys. stat. sol. (b) 232,

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Erratum: Radial oscillations of local density of states in carbon nanotubes [Phys. Rev. B63, 245111 (2001)]

Cited by 10 publications

References 0 publications

W=0pairing in(N,N)carbon nanotubes away from half filling

W=0pairing in(N,N)carbon nanotubes away from half filling

Giant magnetoresistance of multiwall carbon nanotubes: Modeling the tube/ferromagnetic-electrode burying contact

Carbon Nanotube Quantum Dots

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