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.

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.

scholarly journals TIGHT-BINDING PARAMETERS FOR GRAPHENE

2011 ◽  
Vol 25 (03) ◽  
pp. 163-173 ◽  
Author(s):  
RUPALI KUNDU
Keyword(s):  
Band Structure ◽  
Density Of States ◽  
Nearest Neighbor ◽  
Tight Binding ◽  
Nearest Neighbors ◽  
Structure Calculation ◽  
Band Structure Calculation ◽  
First Principle ◽  
Binding Parameters ◽  
Band Dispersion

In this article, we have reproduced the tight-binding π band dispersion of graphene including up to third nearest-neighbors and also calculated the density of states of π band within the same model. The aim was to find out a set of parameters descending in order as distance towards third nearest-neighbor increases compared to that of first and second nearest-neighbors with respect to an atom at the origin. Here we have discussed two such sets of parameters by comparing the results with first principle band structure calculation.1

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.

BAND STRUCTURE OF RHOMBOHEDRAL GRAPHITE

1958 ◽  
Vol 36 (3) ◽  
pp. 352-362 ◽  
Author(s):  
R. R. Haering
Keyword(s):  
Band Structure ◽  
Fermi Surface ◽  
Nearest Neighbor ◽  
Tight Binding ◽  
Rhombohedral Structure ◽  
Hexagonal Prism ◽  
Exchange Integral ◽  
Tight Binding Approximation ◽  
Out Of Plane ◽  
Bernal Stacking

The band structure of rhombohedral graphite has been investigated using the nearest-neighbor tight-binding approximation. The resulting behavior of the π-bands near the Fermi surface is more complex than in the case of the Bernal stacking. The two π-bands still touch, but the touching points no longer lie on the edges of a hexagonal prism in k-space. Instead, they lie on cylinders whose axes are the edges of the hexagonal prism. The radii of these cylinders are proportional to γ1, the nearest "out-of-plane" exchange integral. The de Haas – Van Alphen effect in the rhombohedral structure may be expected to yield useful information about the magnitude of γ1.

scholarly journals Tight-binding Calculations of Band Structure and Conductance in Graphene Nano-ribbons

2009 ◽  
Vol 19 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Hoang Manh Tien ◽  
Nguyen Hai Chau ◽  
Phan Thi Kim Loan
Keyword(s):  
Band Structure ◽  
Electronic Properties ◽  
Nearest Neighbor ◽  
Graphene Nanoribbons ◽  
Tight Binding ◽  
Numerical Calculations ◽  
Dimensional System ◽  
Tight Binding Approximation ◽  
One Dimensional ◽  
Edge Conditions

We suggest a general approach based on the nearest-neighbor tight-binding approximation (TB) to investigate the band structure and conductance of a quasi-one dimensional system. Numerical calculations carried out for Graphene nanoribbons (GNRs) with different widths and edge conditions (zigzag and armchair) reveal the well-known results that the electronic properties of GNRs depend strongly on the size and geometry of the sample.

Electrical Transport Properties of Carbon Nanotube Metal-Semiconductor Heterojunction

2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660009 ◽  
Author(s):  
Keka Talukdar ◽  
Anil Shantappa
Keyword(s):  
Electrical Transport ◽  
Nearest Neighbor ◽  
Electronic Devices ◽  
Tight Binding ◽  
Transmission Function ◽  
Topological Defects ◽  
Dynamics Simulation ◽  
Internal Stresses ◽  
Electrical Transport Properties ◽  
Tight Binding Approximation

Carbon nanotubes (CNTs) have been proved to have promising applicability in various fields of science and technology. Their fascinating mechanical, electrical, thermal, optical properties have caught the attention of today’s world. We have discussed here the great possibility of using CNTs in electronic devices. CNTs can be both metallic and semiconducting depending on their chirality. When two CNTs of different chirality are joined together via topological defects, they may acquire rectifying diode property. We have joined two tubes of different chiralities through circumferential Stone–Wales defects and calculated their density of states by nearest neighbor tight binding approximation. Transmission function is also calculated to analyze whether the junctions can be used as electronic devices. Different heterojunctions are modeled and analyzed in this study. Internal stresses in the heterojunctions are also calculated by molecular dynamics simulation.

Luminescent Amorphous Silicon Layers

1997 ◽  
Vol 486 ◽  
Author(s):  
G. Allan ◽  
C. Delerue ◽  
M. Lannoo
Keyword(s):  
Electronic Structure ◽  
Amorphous Silicon ◽  
Radiative Recombination ◽  
Crystalline Silicon ◽  
Tight Binding ◽  
Blue Shift ◽  
Localized States ◽  
Structure Model ◽  
Radiative Recombination Rate ◽  
Tight Binding Approximation

AbstractThe electronic structure of amorphous silicon layers has been calculated within the empirical tight binding approximation using the Wooten-Winer-Weaire atomic structure model. We predict an important blue shift due to the confinement for layer thickness below 3 nm and we compare with crystalline silicon layers. The radiative recombination rate is enhanced by the disorder and the confinement but remains quite small. The comparison of our results with experimental results shows that the density of defects and localized states in the studied samples must be quite small.

Band structure of silicene in the tight binding approximation

2015 ◽  
Vol 121 (1) ◽  
pp. 115-121 ◽  
Author(s):  
A. V. Gert ◽  
M. O. Nestoklon ◽  
I. N. Yassievich
Keyword(s):  
Band Structure ◽  
Tight Binding ◽  
Tight Binding Approximation

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.

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