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.

Empirical Tight-Binding Applied to Silicon Nanoclusters

1997 ◽  
Vol 491 ◽  
Author(s):  
G. Allan ◽  
C. Delerue ◽  
M. Lannoo
Keyword(s):  
Band Structure ◽  
Nearest Neighbor ◽  
Good Description ◽  
Tight Binding ◽  
Localized States ◽  
Basis Set ◽  
Band Structure Calculation ◽  
Minimal Basis ◽  
Tight Binding Approximation ◽  
Bulk Band

ABSTRACTThe calculation of the electronic structure of silicon nanostructures is used to discuss the accuracy of results obtained by the tight-binding method. We first show that the level of refinement of the tight-binding approximation must be adapted to the calculated property. For example, an accurate description of both the valence and conduction bands which can be achieved with a 3rd-nearest neighbor approximation is necessary to calculate the variation of the gap energy with the silicon crystallite size. The sp3s* model which gives a bad description of the conduction band underestimates the confinement energy but can give good results when it is used to determine the variation of the crystallite band gap with pressure. To study Si-III (BC-8) nanocrystallites, we show that a good description of the bulk band structure can be obtained with non-orthogonal tight-binding but due to the large number of nearest neighbors one must take analytical variations of the parameter with interatomic distances. The parameters involved in these expressions can be easily fitted to the bulk band structures using the k-point symmetry without requiring the use of group theory. Finally we discuss the effect of increasing the size of the minimal-basis set and we show that it would be possible to get the values of the tight-binding parameters from a first-principles localized states band structure calculation avoiding the fit to the energy dispersion curves.

Electronic Structure of Vacancy-Phosphorus Impurity Complexes in Silicon

1989 ◽  
Vol 163 ◽  
Author(s):  
Hongqi Xu ◽  
U. Lindefelt
Keyword(s):  
Electronic Structure ◽  
Function Method ◽  
Energy Levels ◽  
Tight Binding ◽  
Nearest Neighbour ◽  
Binding Theory ◽  
Self Consistent ◽  
Phosphorus Impurity ◽  
Semi Empirical ◽  
Shed Light

AbstractWe present a systematic theoretical investigation on four vacancy-phosphorus impurity complexes in silicon, i.e., a vacancy with one through four phosphorus impurities on the nearest neighbour sites of the vacancy, using a semi-empirical self-consistent tight-binding theory. The calculations are based on the Lanczos-Haydock recursion Green’s function method. The predicted energy levels in the band gap for the five cases, the isolated Si vacancy and the four complexes, show a remarkable regularity. We shed light on this regularity by relating it to the localization of the wavefunctions on the Si and P atoms surrounding the vacancy. We compare our results with experimental work.

Electronic structure of strained layer superlattices from tight binding theory

1988 ◽  
Vol 4 (4-5) ◽  
pp. 511-513 ◽  
Author(s):  
H. Rücker ◽  
F. Bechstedt ◽  
R. Enderlein ◽  
D. Hennig ◽  
S. Wilke
Keyword(s):  
Electronic Structure ◽  
Tight Binding ◽  
Binding Theory ◽  
Strained Layer ◽  
Strained Layer Superlattices

A STUDY ON STRAIN AFFECTING ELECTRONIC STRUCTURE OF WURTZITE ZnO BY FIRST PRINCIPLES

2009 ◽  
Vol 23 (19) ◽  
pp. 2339-2352 ◽  
Author(s):  
LI BIN SHI ◽  
SHUANG CHENG ◽  
RONG BING LI ◽  
LI KANG ◽  
JIAN WEI JIN ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Band Structure ◽  
Valence Band ◽  
Density Of States ◽  
First Principles ◽  
Density Functional ◽  
Functional Theory ◽  
Electron Density Difference ◽  
Different Strains

Density of states and band structure of wurtzite ZnO are calculated by the CASTEP program based on density functional theory and plane-wave pseudopotential method. The calculations are carried out in axial and unaxial strains, respectively. The results of density of states in different strains show that the bottom of the conduction band is always dominated by Zn 4s, and the top of valence band is always dominated by O 2p. The variation of the band gap calculated from band structure is also discussed. In addition, p-d repulsion is used in investigating the variation of the top of the valence band in different strains and the results can be verified by electron density difference.

ab-initio tight-binding theory for the electronic structure

1990 ◽  
Vol 117-118 ◽  
pp. 297-299
Author(s):  
F. Liu ◽  
S.N. Khanna ◽  
P. Jena
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Tight Binding ◽  
Binding Theory

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.

Effect of boron impurity in a carbon nanotube superlattice

2017 ◽  
Vol 31 (14) ◽  
pp. 1750106
Author(s):  
Zahra Karimi Ghobadi ◽  
Aliasghar Shokri ◽  
Sonia Zarei
Keyword(s):  
Carbon Nanotube ◽  
Band Structure ◽  
Boron Atom ◽  
Density Of States ◽  
Nearest Neighbor ◽  
Electronic Band Structure ◽  
Tight Binding ◽  
Topological Defects ◽  
Electronic Band ◽  
Neighbor Approximation

In this work, the influence of boron atom impurity is investigated on the electronic properties of a single-wall carbon nanotube superlattice which is connected by pentagon–heptagon topological defects along the circumference of the heterojunction of these superlattices. Our calculation is based on tight-binding [Formula: see text]-electron method in nearest-neighbor approximation. The density of states (DOS) and electronic band structure in presence of boron impurity has been calculated. Results show that when boron atom impurity and nanotube atomic layers have increased, electronic band structure and the DOS have significant changes around the Fermi level.

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 STRUCTURE OF SEMICONDUCTOR NANOCRYSTALS: AN ACCURATE TIGHT-BINDING DESCRIPTION

2005 ◽  
Vol 04 (05n06) ◽  
pp. 893-899
Author(s):  
SAMEER SAPRA ◽  
RANJANI VISWANATHA ◽  
D. D. SARMA
Keyword(s):  
Electronic Structure ◽  
Excellent Agreement ◽  
Nearest Neighbor ◽  
Semiconductor Nanocrystals ◽  
Tight Binding ◽  
Experimental Results ◽  
Accurate Description ◽  
Orbital Basis ◽  
Theoretical Predictions

We report a quantitatively accurate description of the electronic structure of semiconductor nanocrystals using the sp3d5 orbital basis with the nearest neighbor and the next nearest neighbor interactions. The use of this model for II–VI and III–V semiconductors is reviewed in article. The excellent agreement of the theoretical predictions with the experimental results establishes the feasibility of using this model for semiconductor nanocrystals.

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