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.

HYDROGEN BONDING IN DIAMOND: A COMPUTATIONAL STUDY

2006 ◽  
Vol 17 (07) ◽  
pp. 959-966 ◽  
Author(s):  
O. OFER ◽  
JOAN ADLER ◽  
A. HOFFMAN
Keyword(s):  
Density Of States ◽  
Fermi Energy ◽  
Computational Study ◽  
Tight Binding ◽  
Local Deformation ◽  
Electronic Energy ◽  
Hydrogen Atoms ◽  
High Hydrogen ◽  
New Energy ◽  
Energy States

We present tight binding molecular dynamics simulations of the diffusion and bonding of hydrogen in bulk diamond. The motion of hydrogen atoms and the resultant structural and electronic energy level changes are investigated. The hydrogen atoms were found to have a tendency to migrate to the surface layer of diamond, resulting in a local deformation of the lattice, creating new energy states above and below the Fermi energy in the bandgap of the diamond density of states. In the diamond bulk, at high hydrogen concentrations, vacancies created by a hydrogen atom are quickly filled with other hydrogen atoms causing a deformation of the diamond lattice, inducing H 2 formation. This creates new energy states above the Fermi energy and reduces the secondary bandgap of the diamond density of states.

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

Third Neighbor Analytic Tight-Binding Solutions for Electronic Structure of Carbon Nanosystems

2010 ◽  
Vol 659 ◽  
pp. 197-202
Author(s):  
István László
Keyword(s):  
Electronic Structure ◽  
Tight Binding ◽  
Electronic Structure Calculations ◽  
Diagonal Matrix ◽  
Graphene Sheets ◽  
Matrix Elements ◽  
Structure Calculations

Third neighbor analytic tight-binding formulae were obtained for graphene sheets and nanotubes. After fitting the corresponding of-diagonal matrix elements can be used in numerical electronic structure calculations of nanotubes and corrugated graphene.

Surface Segregation Maps Derived from Tight-Binding Ising Model

2011 ◽  
Vol 172-174 ◽  
pp. 1008-1015 ◽  
Author(s):  
Jean Marc Roussel ◽  
Guy Tréglia ◽  
Bernard Legrand
Keyword(s):  
Experimental Data ◽  
Electronic Structure ◽  
Ising Model ◽  
Surface Energy ◽  
Surface Segregation ◽  
Tight Binding ◽  
Electronic Structure Calculations ◽  
Matrix Elements ◽  
Metal Element ◽  
Structure Calculations

Surface segregation in transition metals can be analysed within a generalised Ising model,derived from Tight-Binding electronic structure calculations, which identifies three driving forces:the difference in surface energy and atomic volume between the two components and their tendencyto order or phase separate in the bulk. Using this ”three effects” rule, we present here general mapswhich predict the tendency of the solute metal element to segregate (or not) at the surface of a metalmatrix, for the 702 solute/matrix systems that can be formed with transition metal elements. Ourpredictions compare fairly well to the existing ab initio calculations and experimental data availableon these systems. The few exceptions, which mainly concern given matrix elements are discussed indetails.

ELECTRONIC STRUCTURE CALCULATIONS FOR MoSe2 USING EXTENDED HUCKEL TIGHT-BINDING METHOD

2004 ◽  
Vol 18 (01) ◽  
pp. 35-44 ◽  
Author(s):  
DONALD H. GALVAN
Keyword(s):  
Electronic Structure ◽  
Density Of States ◽  
Population Analysis ◽  
Tight Binding ◽  
Electronic Structure Calculations ◽  
Total Density ◽  
Mulliken Population Analysis ◽  
Energy Bands ◽  
Mulliken Population ◽  
Structure Calculations

To gain insight into the electronic properties of MoSe 2 (molybdenum selenide, also known as drysdallite), electronic structure calculations, total and projected density of states, crystal orbital overlap population and Mulliken population analysis were performed. The calculated energy bands depict a semiconductor behavior with a direct gap (at K) of 0.91 eV and an indirect gap (from Γ to K) of 3.6 eV, respectively. Total and projected density of states provided information about the contribution from each orbital of each atom to the total density of states. Moreover, the bonding strength between some atoms within the unit cell was obtained. Mulliken population analysis corroborates the electron filling of the Mo dz2 orbitals in agreement with another experimental and theoretical results.

Effects of Molecular Orientational Disorder on the Electronic Structure of K3C60: With the Inclusion of the Tangentially Directed C σ-Orbital

1998 ◽  
Vol 12 (32) ◽  
pp. 3521-3528
Author(s):  
Jing Lu ◽  
Xiangeng Zhao ◽  
Xinwei Zhang ◽  
Liyuan Zhang
Keyword(s):  
Electronic Structure ◽  
Fermi Level ◽  
Conduction Band ◽  
Density Of States ◽  
Tight Binding ◽  
Tight Binding Model ◽  
Orientational Disorder ◽  
Binding Model ◽  
Distance Dependence ◽  
Orbital Approximation

Effects of molecular orientational disorder on the electronic structure of K3C60 are studied using a tight-binding model in which both the 2s and 2p orbitals of C atoms are taken into account. Nearly free of the cut-off distance of the interculster interaction and the form of the distance dependence of the hopping parameters, the orientational disorder always smears out the structure in the conduction-band density of states (DOS), while the value of the DOS at the Fermi level (N(E F )) changes slightly upon disordering. These results are in excellent agreement with the earlier ones based on the single molecular orbital approximation.

Electronic Structure and Total-Energy of FeSi2 Pseudomorphic Phases

1993 ◽  
Vol 320 ◽  
Author(s):  
Leo Miglio ◽  
Giovanna Malegori
Keyword(s):  
Thin Films ◽  
Electronic Structure ◽  
Molecular Beam Epitaxy ◽  
Total Energy ◽  
Density Of States ◽  
Molecular Beam ◽  
Tight Binding ◽  
Binding Parameters ◽  
Annealing Temperatures ◽  
Β Phase

ABSTRACTBy fitting orthogonal tight binding parameters to the ab inlio bands of Calciumfluorite FeSi2 (γ-phase) and Cesiumcloride FeSi, we calculate the electronic structure (bands and density of states) and the total-energy of the semiconductive, orthorombic β-phase and the disordered, cubic one. The latter, the γ and the β nfigurations, have been recently observed at different annealing temperatures in thin films grown on Si (111) by Molecular Beam Epitaxy. The transferability of our method among different phases allows for a comparison of the cohesive energy curves which, in turn, supplies an interpretation of the relative stability and the growth kinetics.

A Tight Binding Model for the Density of States of Graphite-like Structures, Calculated using Green's Functions

1993 ◽  
Vol 46 (5) ◽  
pp. 601 ◽  
Author(s):  
BA McKinnon ◽  
TC Choy
Keyword(s):  
Electronic Structure ◽  
Carbon Fibre ◽  
Density Of States ◽  
Tight Binding ◽  
Analytic Solutions ◽  
Elliptic Integrals ◽  
Experimental Measurements ◽  
Tight Binding Model ◽  
Binding Model ◽  
Densities Of States

The electronic structure of graphite-like materials is investigated within the framework of the tight binding model. The densities of states of simple hexagonal and Bernal graphite are calculated, induding two layer (2D) and bulk (3D) cases. The calculation employs Green's function techniques, resulting in essentially analytic solutions in terms of elliptic integrals. The Bernal density of states is found to agree qualitatively with experimental measurements and the extension of our studies to surface effects and carbon fibre structures is also discussed.

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.

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