Frequency Dependence of Phonon-Induced Current Noise in Armchair Carbon Nanotube

In this study, the thermal behaviour of small-sized single-atom CNTs was examined. CNTs are composed of crystals that form a nanostructure with different geometric shapes by arranging them in different ways according to the length-diameter ratio. Due to the mechanical, electrical, and thermal properties of CNTs, the thermal conduction of CNT materials is critical in controlling the performance and stability of CNTs. CNTs, which are low-dimensional materials with a single atomic layer thickness, have excellent thermal conductivity. According to the simulation technique in ANSYS, CNTs containing the same number of atoms and bonds were developed. The heat transfer of different structures of CNTs in armchairs (6,6) and zig-zag (12,0) were compared. A comparison of zig-zag and armchair CNTs thermal behaviour shows that zig-zag CNTs lattice structure has more advantages than armchair CNTs lattice structure by heat transfer. Highlights In this study, finite element-based thermal analysis of single and double-walled armchair and zig-zag carbon nano-tubes (CNTs) using the lattice method was investigated. A simulation technique was developed and applied in the ANSYS program for single and double-walled carbon nanotubes (CNTs). Armchairs (6,6) and zig-zag (12,0) CNTs in different lattice structures with equal atomic numbers and bond numbers are modelled according to different diameters and length ratios. The CNTs, which have the same material properties as the trays placed at both open ends of the pipes, are kept at different temperature values, and conduction heat transfer behaviour is investigated for certain temperature values. According to the investigated heat conduction behaviour of zig-zag and armchair CNTs, the lattice structure of the zig-zag carbon nano-tubes is more advantageous in terms of heat conduction than the cage structure of armchair CNTs, and it transmits heat faster than the armchair CNTs.

Band gap of carbon nanotubes under combined uniaxial–torsional strain

The effect of topology of single-walled carbon nanotubes (CNTs) on the diffusion dynamics of water confined in the armchair and zigzag CNTs was investigated. It was found that the activation energy of molecular diffusion in zigzag CNTs is greater than that in armchair ones at similar diameters, which leads to water molecules in zigzag CNT diffusing much slower than in armchair CNT. Further calculations of potential energy surfaces (PESs) of water in these two types of CNTs explain the mechanism of diffusion dynamics of confined water. This research shows that the topology of PESs inside CNT could control the diffusion behaviors of water inside it. Since topology of PESs inside CNT could be modified by various chemical and/or physical methods, this work indicates the possibility of controlling the diffusion behaviors inside the CNTs by molecular engineering approach, without changing its pore size.

This paper presents a molecular dynamics (MD) study on the thermally induced buckling of pre-compressed carbon nanotubes (CNTs) using AIREBO interatomic potential. CNTs are compressed at a certain ratio of their critical buckling strain and then undergo a uniform temperature rise. In order to evaluate the chirality effects, armchair and zigzag CNTs are investigated. The results demonstrate that critical buckling temperature depends strongly on the geometrical parameters such as chirality, diameter and aspect ratio. The armchair CNTs, due to their bond configuration, show higher resistance to thermal buckling than zigzag ones. Moreover, the buckling mechanism is strongly affected by the length of CNTs. At small aspect ratios, radial limit load shell buckling occurs while by increase in aspect ratio above the critical one different behaviors emerge. Due to the strong thermal oscillation of carbon atoms, increase in temperature changes perfect nanotubes to defective ones.

Effects of diameter and chirality on structural and dynamical behavior of [EMIM][PF6] encapsulated in carbon nanotube: A molecular dynamics study

Quantum conductance of carbon nanotubes in a wide energy range

In this study, simulated X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were utilized to differentiate the early stage structures as carbon nanobelts (CNBs) evolved into carbon nanotubes (CNTs). The effects of edge type, length, and diameter on the spectroscopic characteristics of armchair and zigzag CNTs were examined. Variations in XPS spectra were found to correspond to changes in the bandgap, while Raman spectra provided distinct bands associated with specific structural features. Notably, in armchair CNTs, the C 1s XPS peak positions exhibited clear differences depending on the structure. Additionally, the Kekulé vibration band and other characteristic bands in Raman spectra varied with length and diameter, enabling differentiation of armchair CNT structures. Although the structural analysis of zigzag CNTs was challenging using XPS, Raman spectroscopy proved to be effective in distinguishing structural differences. This study lays the groundwork for future spectroscopic analyses, contributing to the broader understanding of nanocarbon materials such as CNBs and CNTs and their potential applications in advanced electronic materials.

Molecular dynamics simulations were used to study the removal of Cd(II) as a heavy metal from wastewater using armchair carbon nanotube, boron nitride nanotube and silicon carbide nanotubes under applied electric field. The system contains an aqueous solution of CdCl2 as a heavy metal and a (7,7) nanotube as a nanostructured membrane, embedded in a silicon nitride membrane. An external electric field was applied to the considered system for the removal of Cd2+ through nanotubes. The simulation results show that in the same conditions, considered armchair nanotubes were capable to remove Cd2+ from wastewater with different ratios. Our results reveal that the removal of heavy metals ions through armchair carbon, boron nitride and silicon carbide nanotubes was attributed to the applied electric field. The selective removal phenomenon is explained with the calculation of potential of mean force. Therefore, the investigated systems can be recommended as a model for the water treatment.

Chapter 1 A Shell Theory for Carbon Nanotubes Based on the Interatomic Potential and Atomic Structure

The electronic structure, band gap and density of states of (7,7) Armchair carbon nanotube by the full potentiallin- earized augmented plane wave (FP-LAPW)method in the framework density functional theory (DFT) with the generalized gradient approximation (GGA) were studied. The calculated band structure and density of state of Armchair (7,7) carbon nanotube were in good agreement with theoretical and experimental results.

Magnetic properties of a single iron atomic chain encapsulated in armchair carbon nanotubes: A Monte Carlo study

Fullerenes, boron nitride nanotubes (BNNTs), and carbon nanotubes (CNTs) have all been extensively explored for biomedical purposes. This work describes the use of BNNTs and CNTs as mycolactone inhibitors. Density functional theory (DFT) has been used to investigate the chemical properties and interaction mechanisms of mycolactone with armchair BNNTs (5,5) and armchair CNTs (5,5). By examining the optimized structure and interaction energy, the intermolecular interactions between mycolactone and nanotubes were investigated. The findings indicate that mycolactone can be physically adsorbed on armchair CNTs in a stable condition, implying that armchair CNTs can be potential inhibitors of mycolactone. According to DOS plots and HOMO–LUMO orbital studies, the electronic characteristics of pure CNTs are not modified following mycolactone adsorption on the nanotubes. Because of mycolactone’s large π-π interactions with CNTs, the estimated interaction energies indicate that mycolactone adsorption on CNTs is preferable to that on BNNTs. CNTs can be explored as potentially excellent inhibitors of mycolactone toxins in biological systems.

Water: A comprehensive treatise

Removal of trihalomethanes from aqueous solution through armchair carbon nanotubes: A molecular dynamics study

Interaction between carbon nanotubes and human cell