Effect of interwall interaction on the electronic structure of double-walled carbon nanotubes

Abstract

Through this study, the results of density functional theory calculations within the local density approximation of the electronic structure of zigzag-zigzag double-walled carbon nanotubes (DWCNTs), with chiral indices (n, 0)@(m, 0) for n = 7-15, and m = 15-26, has been presented and the effects of interwall interaction and orbital hybridization on the electronic structure of these systems has been discussed. It was observed that the electronic band gap of the aforementioned DWCNTs depends on the interwall distance only for metallic-semiconductor configurations and on the intrinsic properties of the constituent tubes in all other combinations. It was also observed that the calculated band gap for most of the metallic-metallic DWCNTs was smaller than semiconductor-metallic, metallic-semiconductor, and semiconductor-semiconductor configurations. Metallic-semiconductor DWCNTs were found to be desirable for band gap tuning applications because of their dependence on interwall distance, opening up the possibility of using such systems in electronic device applications, such as transistors. Other applications include the use of DWCNTs in macroscopic carbon nanotube conducting wires, for which metallic-metallic and semiconducting-metallic zigzag-zigzag DWCNTs were found to be the most desirable configurations due to their small band gaps.

A Review of Double-Walled and Triple-Walled Carbon Nanotube Synthesis and Applications

“…Moreover, the effectiveness of this mixing is directly related to the van der Waals forces mediating the interlayer interactions. In other words, for weak IL interactions, the tubes composing the multi-walled systems would behave independently of each other [30][31][32][33][34][35][36][37][38]54,55]. In fact, DWNTs can show up in four different flavors (inner tube@outer tube), as shown in Figure 3a, while TWNTs present eight different flavors (inner tube@middle tube@outer tube), as depicted in Figure 3b.…”

“…The magnitude of these IL interactions will change according to the chirality combinations between the pairs (n, m)@(n , m ) in a DWNT or among the set (n, m)@(n , m )@(n , m ) in a TWNT [30][31][32][33][34][35][36][37][38]. Namely, Saito et al predicted that the IL interactions would play different roles in the DWNT structure and showed that the stability of the double-walled structure does not strongly depend on the (n, m) pairs of the tubes constituting the DWNT, but the van der Waals-related barrier potential for the relative motion of the inner and outer tubes depends strongly on the (n, m) pairs [38].…”

“…It had been common sense that incommensurate systems would not present IL interactions capable of changing the electronic and vibrational properties of the individual SWNT constituting the multi-walled carbon nanotubes [30][31][32][33][34][35][36][37][38]54,55]. On the other hand, commensurate systems would present IL interactions strong enough to perturb the electronic and vibrational structures of the SWNTs constituting the multi-walled tubes [30][31][32][33][34][35][36][37][38]54,55]. However, as discussed below, incommensurate tubes may present Moiré patterns, and in these cases, the IL interactions cannot be neglected [54,55].…”

Ab Initio Study of Iodine-Doped Carbon Nanotube Conductors

“…Over the course of the last two decades, considerable experimental research has investigated the conduction performance of single wall carbon nanotubes [7], multiwall carbon nanotubes ( [8], doped CNT [3,[9][10][11][12], CNT composites [13,14], CNT junctions [15], and CNT networks [16]. Complimentary computational research on these topics has also been performed, although the ab initio computational literature has modeled rather simple systems [11], due in large part to high computational cost.…”

“…The previous work on CNT conductors has included studies of (1) defects (e.g., vacancies [22]), (2) chemical doping (e.g., F [23], I 2 , ICl, IBr [11], MoO 3 [24], and AuCl 3 [25]), (3) multiwall CNT systems (e.g., a double wall CNT in which each tube has different electrical properties [26] or a double wall CNT with variations in the interwall spacing [8]), and (4) the performance of nanocomposite wires (e.g., copper-CNT conductors [27] and sulfur chains positioned inside CNT [28]). Some research has investigated such parameters acting in combination.…”