ELECTRONIC STRUCTURE OF GaxIn1-xASyP1-y QUATERNARY ALLOY BY RECURSION METHOD

1999 ◽  
Vol 13 (01) ◽  
pp. 97-106 ◽  
Author(s):  
MUSA EL-HASAN
Keyword(s):  
Electronic Structure ◽  
Density Of States ◽  
Local Density ◽  
Tight Binding ◽  
Quaternary Alloy ◽  
Integrated Density Of States ◽  
Recursion Method ◽  
Zinc Blend ◽  
Orbital Decomposition ◽  
Lattice Matched

The electronic structure of Ga x In 1-x As y P 1-y quaternary alloy, calculated by recursion method is reported. A five orbitals sp3s* per atom model was used in the tight-binding representation of the Hamiltonian. The local density of states and its orbital decomposition (LDOS), integrated density of states (IDOS) and structural energy (STE) were calculated for Ga, In, As and P sites in Ga 0.5 In 0.5 As 0.5 P 0.5, GaInAsP lattice matched to InP and lattice matched to GaAs as well. There are 216 atoms arranged in a zinc-blend structure. The calculated quantities are as expected for such systems.

ENERGY GAP DEPENDENCE ON ANION CONCENTRATION FOR GaxIn1-xAsyP1-y QUATERNARY ALLOY BY RECURSION METHOD

2004 ◽  
Vol 18 (18) ◽  
pp. 955-962
Author(s):  
MUSA EL-HASAN ◽  
REZEK ESTATIEH
Keyword(s):  
Density Of States ◽  
Energy Gap ◽  
Local Density ◽  
Tight Binding ◽  
Quaternary Alloy ◽  
Average Density ◽  
Local Density Of States ◽  
Recursion Method ◽  
Orbital Decomposition ◽  
Lattice Matched

Three terminators have been tested, square root terminator, quadreture terminator and linear terminator, it was found that the linear terminator is the best, so it was used in calculating local density of states (LDOS) and it's orbital decomposition, alloy average density of states, and energy gap for different anion concentrations for InP lattice matched alloy. The results were compared with our previous calculations of (LDOS), and results from other methods. Energy gap was compared with experimental measurements. A five orbital sp3s* per atom model was used in the tight-binding representation of the Hamiltonian.

scholarly journals Augmented Space Recursion Method for the Study of Electronic States of Binary Alloys

1970 ◽  
Vol 44 (3) ◽  
pp. 255-264
Author(s):  
M Abdus Salam ◽  
Kabir Ahmed ◽  
BP Barua ◽  
MSI Aziz
Keyword(s):  
Electronic Structure ◽  
Density Of States ◽  
Tight Binding ◽  
Electronic States ◽  
Density Of State ◽  
Recursion Method ◽  
Disordered Alloys ◽  
Lmto Method ◽  
Augmented Space ◽  
Space Formalism

We have studied here the electronic structure of pure random disordered alloys formed by Ni with Cu and Au at different ratios by using the linearized tight-binding muffin-tin Orbital (TB-LMTO) method. We also used the recursion technique together with augmented space formalism for increasing the efficiency and the accuracy to calculate the component projected density of states. From the density of state, we can understand the Fermi energy, magnetic moment and binding energy at different alloy compositions. The band structure can be calculated from here also. These studies are helpful for experimentalists and metallurgists in designing materials and alloys with specific properties. Key words: Electronic structure, Alloys, TB-LMTO, Density of states, Augmented space recursion   DOI: 10.3329/bjsir.v44i3. Bangladesh J. Sci. Ind. Res. 44(3), 255-264, 2009

scholarly journals ELECTRONIC STATES AND LOCAL DENSITY OF STATES NEAR GRAPHENE CORNER EDGE

2012 ◽  
Vol 11 ◽  
pp. 151-156 ◽  
Author(s):  
YUJI SHIMOMURA ◽  
YOSITAKE TAKANE ◽  
KATSUNORI WAKABAYASHI
Keyword(s):  
Density Of States ◽  
Nearest Neighbor ◽  
Local Density ◽  
Tight Binding ◽  
Localized States ◽  
Destructive Interference ◽  
Edge States ◽  
Local Density Of States ◽  
Binding Model ◽  
Recursion Method

We study that stability of edge localized states in semi-infinite graphene with a corner edge of the angles 60°, 90°, 120° and 150°. We adopt a nearest-neighbor tight-binding model to calculate the local density of states (LDOS) near each corner edge using Haydock's recursion method. The results of the LDOS indicate that the edge localized states stably exist near the 60°, 90°, and 150° corner, but locally disappear near the 120° corner. By constructing wave functions for a graphene ribbon with three 120° corners, we show that the local disappearance of the LDOS is caused by destructive interference of edge states and evanescent waves.

NUMERICAL APPLICATION OF THE RECURSION METHOD TO THE ELECTRONIC STRUCTURE OF C60

1996 ◽  
Vol 10 (23) ◽  
pp. 1133-1139 ◽  
Author(s):  
JING LU ◽  
LIYUAN ZHANG
Keyword(s):  
Electronic Structure ◽  
Energy Spectrum ◽  
Density Of States ◽  
Nearest Neighbor ◽  
Tight Binding ◽  
Icosahedral Symmetry ◽  
Numerical Application ◽  
Recursion Method ◽  
Valence Electrons ◽  
Π State

The recursion method is applied to study the electronic structure of a neutral C 60 molecule by numerically computing the density of states (DOS). A tight-binding Hamiltonian which considers the s and p valence electrons of carbon is used, and the coupling between orbitals is described by Harrison’s hopping formula. We obtain the overall molecular energy spectrum. The sequence orders and the degeneracies of π state levels, obtained when considering a mixture of the orbitals, agree well with those from the analytical method. We find that the inclusion of a nonzero next-nearest-neighbor hopping and even the inclusion of a nonzero next-next-nearest-neighbor hopping do not destroy icosahedral symmetry.

ELECTRONIC STRUCTURE OF STRAINED VANADIUM OVERLAYERS ON W(100) AND Ta(100)

1996 ◽  
Vol 03 (04) ◽  
pp. 1505-1509 ◽  
Author(s):  
R. DE COSS
Keyword(s):  
Electronic Structure ◽  
Density Of States ◽  
Lattice Mismatch ◽  
Local Density ◽  
Tight Binding ◽  
Local Density Of States ◽  
Tight Binding Approximation ◽  
Surface Electronic Structure ◽  
Topmost Layer ◽  
Surface Green Function

We study the role of hybridization and overlayer–substrate lattice mismatch in determining the surface electronic structure of strained V monolayers and bilayers on W(100) and Ta(100). The local density of states is calculated in the tight-binding approximation within the surface-Green-function-matching formalism. For one monolayer of V on W(100) and Ta(100), the strong monolayer–substrate 3d–5d hybridization determines the features of the surface local density of states, with essentially no differences between 1V/W(100) and 1V/Ta(100). For the bilayer we find that the electronic structure of the topmost layer depends strongly on the lattice mismatch between overlayer and substrate. In particular, we find that the surface local density of states at the Fermi level in 2V/Ta(100) is 69% higher than in 1V/Ta(100); the lattice mismatch between bulk constants of V and Ta is 9.0%. These results indicate that strain induces strong band narrowing in vanadium overlayers on transition metals, despite the large overlayer–substrate hybridization, but depends critically on the film thickness.

Tight Binding Modeling of Properties Related to Field Emission from Nanodiamond Clusters

2000 ◽  
Vol 621 ◽  
Author(s):  
Denis A. Areshkin ◽  
Olga A. Shenderova ◽  
Victor V. Zhirnov ◽  
Alexander F. Pal ◽  
John J. Hren ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Field Emission ◽  
Density Of States ◽  
Electron Affinity ◽  
Potential Distribution ◽  
Tight Binding ◽  
Matrix Elements ◽  
Energy States ◽  
Bulk Diamond ◽  
Modeling Of Properties

ABSTRACTThe electronic structure of nanodiamond clusters containing between 34 and 913 carbon atoms was calculated using a tight-binding Hamiltonian. All clusters had shapes represented by an octahedron with (111) facets with the top and the bottom vertices truncated to introduce (100) surfaces. The tight-binding Hamiltonian consisted of environment-dependent matrix elements, and C-H parameters fit to reproduce energy states of the cyclic C6 and methane. The calculations predict a density of states similar to bulk diamond for clusters with radii greater than ∼2.5nm, and insignificant differences in the potential distribution between the clusters and bulk diamond for radii greater than ∼1nm. Hydrogen passivated nanodiamond clusters are estimated to have an electron affinity of approximately -1.8 eV.

Electronic band structure of silver low-index surfaces: a tight-binding study

2020 ◽  
Vol 98 (5) ◽  
pp. 488-496
Author(s):  
H.J. Herrera-Suárez ◽  
A. Rubio-Ponce ◽  
D. Olguín
Keyword(s):  
Band Structure ◽  
Density Of States ◽  
Electronic Band Structure ◽  
Local Density ◽  
Tight Binding ◽  
Theoretical Data ◽  
Binding Study ◽  
Local Density Of States ◽  
Electronic Band ◽  
Tight Binding Method

We studied the electronic band structure and corresponding local density of states of low-index fcc Ag surfaces (100), (110), and (111) by using the empirical tight-binding method in the framework of the Surface Green’s Function Matching formalism. The energy values for different surface and resonance states are reported and a comparison with the available experimental and theoretical data is also done.

Electronic Structure vs Phase in Al3V

1988 ◽  
Vol 141 ◽  
Author(s):  
J.-H. Xu
Keyword(s):  
Electronic Structure ◽  
Bulk Modulus ◽  
Total Energy ◽  
Crystal Structures ◽  
Lattice Constant ◽  
Density Of States ◽  
Phase Stability ◽  
Local Density ◽  
Young Modulus ◽  
Good Agreement

AbstractThe electronic structure of Al3V vs its two different crystal structures (DO22 and Ll2) were investigated using local density total energy approach. The calculated results of the total energy showed that in Al3V the tetragonal DO22 phase is energetically favored as compared to the cubic Ll2 phase, the total energy in the former case is about 60 mRy/F.U. lower than that in the later case. The calculated lattice constant (a=3.72 Å, c=8.20 Å) is in fairly good agreement with experiment (a=3.778 Å, c=8.326 Å),and the bulk modulus (1.3 Mbar) is comparable with the experimental Young modulus (150 GPa) for Al3Ti. Furthermore, it is interesting to note that the density of states at EF in the tetragonal DO22 phase (0.14 states/eV-F.U.) is about one order magnitude smaller than that in the Ll2 phase (2.89 states/eV-F.U.). The electronic structure of Al3V seems to be fairly satisfactory in explaining its phase stability.

scholarly journals The t2g – eg band splitting of atoms on a rough surface

2015 ◽  
Vol 39 (1) ◽  
pp. 37-43
Author(s):  
Ain Ul Huda ◽  
Taskeya Haider ◽  
Supriya Saha ◽  
Mesbahuddin Ahmed
Keyword(s):  
Molecular Beam Epitaxy ◽  
Rough Surface ◽  
Density Of States ◽  
Molecular Beam ◽  
Tight Binding ◽  
Orbital Method ◽  
Recursion Method ◽  
Academy Of Sciences ◽  
Ag Substrate ◽  
Deposition Techniques

Any deposition techniques lead to the production of rough surfaces. Some researchers proposed a pair of coupled continuum equations, which models the molecular beam epitaxy. This model was used to generate a rough surface of Fe, which is deposited on a Ag substrate. Then use of recursion method of Haydock with the parameter of tight binding linearized muffin tin orbital method of Anderson revealed that the t2g and eg bands are nondegenerate at bulk and [100] plane but near the rough surface, the degeneracy is broken and splitting of density of states depends on the curvature of the surface.Journal of Bangladesh Academy of Sciences, Vol. 39, No. 1, 37-43, 2015

Electronic Structure for a Distorted Chain

1972 ◽  
Vol 50 (11) ◽  
pp. 1078-1081
Author(s):  
T. C. Wong ◽  
B. Y. Tong
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Density Of States ◽  
Energy Levels ◽  
Linear Chain ◽  
Integrated Density Of States ◽  
Counting Method ◽  
Model Liquid ◽  
Impurity Atoms ◽  
Specific Manner

A linear chain with impurities randomly distributed along it is studied by means of the node counting method. The host atoms as well as the impurity atoms are represented by negative δ-function potentials with different strengths. The solvent atoms are distorted in a specific manner about each impurity atom. The integrated density of states are calculated near a band gap for different impurity concentrations and for various degrees of distortion. It was found that without distortion the gap remains practically structureless, whereas with distortion the energy levels diffuse into the gap. The results are qualitatively similar to that of a model liquid.

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