scholarly journals Symmetry-adapted tight-binding electronic structure analysis of carbon nanotubes with defects, kinks, twist, and stretch

2020 ◽  
pp. 108128652096183
Author(s):  
Soumya Mukherjee ◽  
Hossein Pourmatin ◽  
Yang Wang ◽  
Timothy Breitzman ◽  
Kaushik Dayal
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Band Structure ◽  
Tight Binding ◽  
Numerical Approach ◽  
Computational Method ◽  
Computational Domain ◽  
Perfectly Matched Layers ◽  
Vacancy Defects ◽  
Semiconducting Nanotubes

In this paper, a symmetry-adapted method is applied to examine the influence of deformation and defects on the electronic structure and band structure in carbon nanotubes. First, the symmetry-adapted approach is used to develop the analog of Bloch waves. Building on this, the technique of perfectly matched layers is applied to develop a method to truncate the computational domain of electronic structure calculations without spurious size effects. This provides an efficient and accurate numerical approach to compute the electronic structure and electromechanics of defects in nanotubes. The computational method is applied to study the effect of twist, stretch, and bending, with and without various types of defects, on the band structure of nanotubes. Specifically, the effect of stretch and twist on band structure in defect-free conducting and semiconducting nanotubes is examined, and the interaction with vacancy defects is elucidated. Next, the effect of localized bending or kinking on the electronic structure is studied. Finally, the paper examines the effect of 5–8–5 Stone–Wales defects. In all of these settings, the perfectly matched layer method enables the calculation of localized non-propagating defect modes with energies in the bandgap of the defect-free nanotube.

ELECTRONIC STATES OF NANOSTRUCTURES OF CURVED GRAPHITIC CARBON CAGES

1996 ◽  
Vol 03 (01) ◽  
pp. 835-842 ◽  
Author(s):  
M. TSUKADA ◽  
K. AKAGI ◽  
R. TAMURA ◽  
S. IHARA
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Systematic Study ◽  
Tight Binding ◽  
Electronic States ◽  
Graphitic Carbon ◽  
Graphitic Layer ◽  
Binding Models ◽  
Structure Of Carbon Nanotubes

Electronic structure of carbon nanotubes with cap and that of the helically coiled nanotubes are studied by the simple tight-binding models. The method of the development map is used for a systematic study of the electronic states. Several remarkable features of these cage structures are found and the relation to the topological disorders due to the disclination centers is discussed, which are inherent to the curved graphitic layer.

A Tight-Binding Hamiltonian for the High-Temperature Superconductor YBa2Cu3O7

1988 ◽  
Vol 141 ◽  
Author(s):  
M.J. DeWeert ◽  
D.A. Papaconstantopoulos ◽  
W.E. Pickett
Keyword(s):  
Electronic Structure ◽  
High Temperature ◽  
Band Structure ◽  
Potential Application ◽  
Oxygen Vacancies ◽  
High Temperature Superconductor ◽  
Tight Binding ◽  
Coherent Potential Approximation ◽  
Potential Approximation

AbstractWe present a highly accurate tight-binding parametrization of the LAPW band structure of the high-temperature superconductor YBa2Cu3O7, discuss the methodology used in obtaining this fit, and its potential application to a Tight-Binding Coherent-Potential Approximation (TB-CPA) calculation of the effects of oxygen vacancies on the electronic structure.

Tight Binding Modelling of Energy Band Structure in Nitride Heterostructures

2008 ◽  
Vol 8 (2) ◽  
pp. 540-548 ◽  
Author(s):  
Özden Akıncı ◽  
H. Hakan Gürel ◽  
Hilmi Ünlü
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Valence Band ◽  
Nearest Neighbor ◽  
Good Description ◽  
Energy Levels ◽  
Tight Binding ◽  
Binding Theory ◽  
Orbit Splitting ◽  
Atomic Energy Levels

We studied the electronic structure of group III–V nitride ternary/binary heterostructures by using a semi-empirical sp3s* tight binding theory, parametrized to provide accurate description of both valence and conductions bands. It is shown that the sp3s* basis, along with the second nearest neighbor (2NN) interactions, spin-orbit splitting of cation and anion atoms, and nonlinear composition variations of atomic energy levels and bond length of ternary, is sufficient to describe the electronic structure of III–V ternary/binary nitride heterostructures. Comparison with experiment shows that tight binding theory provides good description of band structure of III–V nitride semiconductors. The effect of interface strain on valence band offsets in the conventional Al1−xGaxN/GaN and In1−xGaxN/GaN and dilute GaAs1−xNx/GaAs nitride heterostructures is found to be linear function of composition for the entire composition range (0 ≤ x ≤ 1) because of smaller valence band deformations.

ELECTRONIC STRUCTURE AND QUANTUM PHASE TRANSITION IN MULTI-WALL CARBON NANOTUBES

2007 ◽  
Vol 21 (25) ◽  
pp. 4377-4386 ◽  
Author(s):  
SHI-DONG LIANG
Keyword(s):  
Phase Transition ◽  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Quantum Phase Transition ◽  
Essential Role ◽  
Energy Gap ◽  
Tight Binding ◽  
Quantum Phase ◽  
Multi Wall Carbon Nanotubes ◽  
Structure Characteristics

The electronic structure of the multi-wall carbon nanotubes (MWCN) is studied theoretically by the tight-binding approach. The interwall coupling between layers plays an essential role in the electronic structure. With an increase of the interwall coupling, the energy gap of the semiconducting MWCNs will decrease and eventually vanish, giving rise to the semiconductor–metal quantum phase transition. The metallic layer in the MWCN dominates the electronic structure characteristics near the Fermi level (gapless).

Orbitals and bands at metal surfaces: photoemission from the {110} surface of tungsten

1981 ◽  
Vol 376 (1767) ◽  
pp. 565-583 ◽  
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Surface State ◽  
Photon Emission ◽  
Tight Binding ◽  
Tight Binding Approximation ◽  
The Third ◽  
Surface Brillouin Zone ◽  
Orbital Character ◽  
Bulk Band

The electronic structure of the {110} surface of tungsten has been investigated by using angle-resolved photoemission. A surface state has been identified and characterized throughout the surface Brillouin zone (s. B. z.). Its dispersion is found to correlate with the projected band gap between the third and fourth bands of the tungsten bulk band structure. It is identified by comparison with Inglesfield’s calculation as having predominantly m = 1 d-orbital character. With photon energies of 21.2 and 40.8 eV, intense photoemission from the surface state is only observed after surface Umklapp, whereas, with 16.8 eV, photon emission is observed in both the first and second s. B. zs. The applicability of the tight-binding approximation to the elucidation of the electronic structure of a metal surface is examined with particular reference to this surface state. A qualitative analysis of the observed photoemission intensities is consistent with emission from a tungsten e g orbital that is hybridized with e g orbitals on neighbouring atoms.

scholarly journals Electronic Structure of Substitutionally Disordered Alloys: Direct Configurational Averaging

1992 ◽  
Vol 278 ◽  
Author(s):  
C. Wolverton ◽  
D. De Fontaine ◽  
H. Dreysse ◽  
G. Ceder
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Local Density ◽  
Tight Binding ◽  
Ternary Alloys ◽  
Orbital Method ◽  
Thermodynamic Quantities ◽  
Local Density Of States ◽  
Disordered Alloys ◽  
Effective Cluster

AbstractThe method of direct configurational averaging (DCA) has been proposed to study the electronic structure of disordered alloys. Local density of states and band structure energies are obtained by averaging over a small number of configrations within a tight-binding Hamiltonian. Effective cluster interactions, the driving quantities for ordering in solids, are computed for various alloys using a tight-binding form of the linearized muffin-tin orbital method (TB-LMTO). The DCA calculations are used to determine various energetic and thermodynamic quantities for binary and ternary alloys.

Tight-Binding Study of the Electronic Structure of the high Temperature Superconductor La2CuO4

1987 ◽  
Vol 99 ◽  
Author(s):  
D. A. Papaconstantopoulos ◽  
M. J. Deweert ◽  
W. E. Pickett
Keyword(s):  
Electronic Structure ◽  
High Temperature ◽  
Band Structure ◽  
Fermi Surface ◽  
First Principles ◽  
High Temperature Superconductor ◽  
Tight Binding ◽  
Binding Study ◽  
Three Components

ABSTRACTWe have fit our first principles LAPW band structure results for the high Tc superconductor La2CuO4 to a tight-binding Hamiltonian that contains s, p, and d interactions from the three components of these materials. Our fit reproduces very accurately the 17 lower bands of this material and especially the Fermi surface.

scholarly journals From Cyclic Nanorings to Single-Walled Carbon Nanotubes: Disclosing the Evolution of their Electronic Structure with the Help of Theoretical Methods

2018 ◽  
Author(s):  
Andrés Pérez Guardiola ◽  
Ricardo Ortiz-Cano ◽  
María Eugenia Sandoval-Salinas ◽  
Joaquín Fernández-Rossier ◽  
David Casanova ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Chemical Nature ◽  
Occupation Number ◽  
Tight Binding ◽  
Finite Size ◽  
Electronic Effects ◽  
Structural Modifications ◽  
End Caps ◽  
Walled Carbon Nanotubes

We systematically investigate the relationships between structural and electronic effects of finite size zigzag or armchair carbon nanotubes of various diameters and lengths, starting from a molecular template of varying shape and diameter, i.e. cyclic oligoacene or oligophenacene molecules, and disclosing how adding layers and/or end-caps (i.e. hemi-fullerenes) can modify their (poly)radicaloid nature. We mostly used tight-binding and finite-temperature density-based methods, the former providing a simple but intuitive picture about their electronic structure, and the latter dealing effectively with strong correlation effects by relying on a fractional occupation number weighted electron density (ρ<sub>FOD</sub>), with additional RAS-SF calculations backing up the<br>latter results. We also explore how minor structural modifications of nanotube end-caps might influence the results, showing that topology, together with the chemical nature of the systems, is pivotal for the understanding of the electronic properties of these and other related systems.

scholarly journals From Cyclic Nanorings to Single-Walled Carbon Nanotubes: Disclosing the Evolution of their Electronic Structure with the Help of Theoretical Methods

2018 ◽  
Author(s):  
Andrés Pérez Guardiola ◽  
Ricardo Ortiz-Cano ◽  
María Eugenia Sandoval-Salinas ◽  
Joaquín Fernández-Rossier ◽  
David Casanova ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Chemical Nature ◽  
Occupation Number ◽  
Tight Binding ◽  
Finite Size ◽  
Electronic Effects ◽  
Structural Modifications ◽  
End Caps ◽  
Walled Carbon Nanotubes

We systematically investigate the relationships between structural and electronic effects of finite size zigzag or armchair carbon nanotubes of various diameters and lengths, starting from a molecular template of varying shape and diameter, i.e. cyclic oligoacene or oligophenacene molecules, and disclosing how adding layers and/or end-caps (i.e. hemi-fullerenes) can modify their (poly)radicaloid nature. We mostly used tight-binding and finite-temperature density-based methods, the former providing a simple but intuitive picture about their electronic structure, and the latter dealing effectively with strong correlation effects by relying on a fractional occupation number weighted electron density (ρ<sub>FOD</sub>), with additional RAS-SF calculations backing up the<br>latter results. We also explore how minor structural modifications of nanotube end-caps might influence the results, showing that topology, together with the chemical nature of the systems, is pivotal for the understanding of the electronic properties of these and other related systems.

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