DISORDER INDUCED DENSITY OF STATES WITHIN THE BAND GAP

1981 ◽  
Vol 42 (C4) ◽  
pp. C4-59-C4-62
Author(s):  
H. Leschke ◽  
B. Kramer
Keyword(s):  
Band Gap ◽  
Density Of States

Theoretical study of modified electron band dispersion and density of states due to high frequency phonons in graphene-on-substrates

2018 ◽  
Vol 07 (04) ◽  
pp. 1850024
Author(s):  
Sivabrata Sahu ◽  
G. C. Rout
Keyword(s):  
Band Gap ◽  
Density Of States ◽  
High Frequency ◽  
Vibrational Energy ◽  
Harmonic Approximation ◽  
Coulomb Energy ◽  
Electron Band ◽  
Band Dispersion ◽  
Energy Formula ◽  
Sublattice Site

We propose here a theoretical model for the study of band gap opening in graphene-on- polarizable substrate taking the effect of electron–electron and electron–phonon (EP) interactions at high frequency phonon vibrations. The Hamiltonian consists of hopping of electrons upto third nearest- neighbors and the effect substrate, where A sublattice site is raised by energy [Formula: see text] and B sublattice site is suppressed by energy [Formula: see text], hence producing a band gap energy of [Formula: see text]. Further, we have considered Hubbard type electron–electron repulsive interactions at A and B sublattices, which are considered within Hartree–Fock meanfield approximation. The electrons in the graphene plane interact with the phonon’s present in the polarized substrate in the presence of phonon vibrational energy within harmonic approximation. The temperature-dependent electron occupancies are computed numerically and self-consistently for both spins at both the sublattice sites. By using these electron occupancies, we have calculated the electron band dispersion and density of states (DOS), which are studied for the effects of EP interaction, high phonon frequency, Coulomb energy and substrate induced gap.

Position dependence of local density of states in 3D band gap of a finite photonic crystal

2021 ◽  
Author(s):  
Charalampos P. Mavidis ◽  
Anna C. Tasolamprou ◽  
Shakeeb B. Hasan ◽  
Thomas Koschny ◽  
Eleftherios N. Economou ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Band Gap ◽  
Density Of States ◽  
Local Density ◽  
Local Density Of States ◽  
Position Dependence

THE HOT CARRIER TEMPERATURE IN THE ANALYSIS OF THE FREE TO ACCEPTOR PHOTOLUMINESCENCE TRANSITION

2001 ◽  
Vol 15 (17n19) ◽  
pp. 696-699 ◽  
Author(s):  
G. Fonthal ◽  
M. de los Rios ◽  
J. Quintero ◽  
N. Piraquive ◽  
H. Ariza-Calderón
Keyword(s):  
Fermi Level ◽  
Band Gap ◽  
Density Of States ◽  
Impurity Concentration ◽  
Lattice Temperature ◽  
Band Tail ◽  
Hot Carrier ◽  
Additional Information ◽  
Carrier Temperature ◽  
Shape Equation

We analyzed the free to acceptor (e-A) photoluminescence transition on a GaAs:Ge sample using the hot carrier temperature and the Kane's DOS. This latter temperature was calculated by the spectra largest energy tail. While the lattice temperature was put in the e-A Eagles' shape equation, the fitting was poor but if the modified line was put into the equation, the fitting was better. So, the ionization impurity energy, the band gap, the Fermi level and the band tail can be measured with a better precision than the measurements traditionally made with this method, Additional information about phonons participant can be obtained. In conclusion, the hot carrier temperature and the density of states due to the impurity concentration should be used in the e-A transition photoluminescence analysis.

scholarly journals Finite-size Scaling of the Density of States in Photonic Band Gap Crystals

2018 ◽  
Vol 120 (23) ◽  
Author(s):  
Shakeeb Bin Hasan ◽  
Allard P. Mosk ◽  
Willem L. Vos ◽  
Ad Lagendijk
Keyword(s):  
Band Gap ◽  
Density Of States ◽  
Photonic Band Gap ◽  
Finite Size ◽  
Finite Size Scaling ◽  
Size Scaling ◽  
Photonic Band

Electronic Properties of Calcium and Zirconium Co-Doped BaTiO3

2020 ◽  
Vol 1010 ◽  
pp. 308-313
Author(s):  
Akeem Adekunle Adewale ◽  
Abdullah Chik ◽  
Ruhiyuddin Mohd Zaki
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Density Of States ◽  
Energy Band ◽  
Density Functional ◽  
Partial Density ◽  
Total Density ◽  
Energy Band Gap ◽  
Wide Energy ◽  
Direct Band

Barium titanate (BaTiO3) is a perovskite based oxides with many potential application in electronic devices. From experimental report BaTiO3 has wide energy band gap of about 3.4 eV which by doped with Ca and Zr at A- and B- sites respectively can enhance their piezoelectric properties. Using first principles method within the density functional theory (DFT) as implement in Quantum Espresso (QE) with the plane wave pseudo potential function, the influence of the Ca and Zr doping in BaTiO3 are studied via electronic properties: band structure, total density of states (TDOS) and partial density of states (PDOS). The energy band gap calculated was underestimation which is similar to other DFT work. Two direct band gap where observed in Ba0.875Ca0.125Ti0.875Zr0.125O3 sample at Γ- Γ (2.31 eV) and X- X (2.35 eV) symmetry point.

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.

The Kohn-Sham density of states and band gap of water: From small clusters to liquid water

2005 ◽  
Vol 123 (5) ◽  
pp. 054510 ◽  
Author(s):  
P. Cabral do Couto ◽  
S. G. Estácio ◽  
B. J. Costa Cabral
Keyword(s):  
Band Gap ◽  
Density Of States ◽  
Liquid Water ◽  
Small Clusters
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