Electronic band structure of layers within meta generalized gradient approximation of density functionals

2020 ◽  
Vol 102 (4) ◽  
Author(s):  
Abhilash Patra ◽  
Bikash Patra ◽  
Lucian A. Constantin ◽  
Prasanjit Samal
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Density Functionals ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Generalized Gradient Approximation

Ab initio calculation on the Optical Properties of AA- Stacked two dimensional Graphene, Silicene, Germanene, and Stanene

2018 ◽  
Vol 1 (1) ◽  
pp. 46-50
Author(s):  
Rita John ◽  
Benita Merlin
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Complex Refractive Index ◽  
Single Layer ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Wide Range ◽  
Optical Region

In this study, we have analyzed the electronic band structure and optical properties of AA-stacked bilayer graphene and its 2D analogues and compared the results with single layers. The calculations have been done using Density Functional Theory with Generalized Gradient Approximation as exchange correlation potential as in CASTEP. The study on electronic band structure shows the splitting of valence and conduction bands. A band gap of 0.342eV in graphene and an infinitesimally small gap in other 2D materials are generated. Similar to a single layer, AA-stacked bilayer materials also exhibit excellent optical properties throughout the optical region from infrared to ultraviolet. Optical properties are studied along both parallel (||) and perpendicular ( ) polarization directions. The complex dielectric function (ε) and the complex refractive index (N) are calculated. The calculated values of ε and N enable us to analyze optical absorption, reflectivity, conductivity, and the electron loss function. Inferences from the study of optical properties are presented. In general the optical properties are found to be enhanced compared to its corresponding single layer. The further study brings out greater inferences towards their direct application in the optical industry through a wide range of the optical spectrum.

scholarly journals Ab-initio study of the orthorhombic ndmno3 perovskite

2014 ◽  
Vol 70 (a1) ◽  
pp. C1806-C1806
Author(s):  
Samir Bentata ◽  
Bouabdellah Bouadjemi ◽  
Tayeb Lantri ◽  
Wissem Benstaali
Keyword(s):  
Density Functional ◽  
Electronic Band Structure ◽  
Total Density ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Functional Theory ◽  
Half Metallic ◽  
Generalized Gradient Approximation ◽  
Ferromagnetic Ground State ◽  
Total Density Of States

We investigate the structural, electronic and magnetic properties of the orthorhombic Perovskite oxyde NdMnO3 through density-functional-theory (DFT) calculations using both generalized gradient approximation GGA+U, where U is on-site Coulomb interaction correction. The electronic band structure, the partial and total density of states (DOS) and the magnetic moment are determined. The results show a half-metallic ferromagnetic ground state for the orthorhombic NdMnO3.

ELECTRONIC AND ELASTIC PROPERTIES OF ZINC-BLENDE MgSe

2013 ◽  
Vol 27 (09) ◽  
pp. 1350027 ◽  
Author(s):  
B. I. ADETUNJI ◽  
P. O. ADEBAMBO ◽  
J. O. AKINLAMI ◽  
G. A. ADEBAYO
Keyword(s):  
Band Structure ◽  
Elastic Properties ◽  
Cohesive Energy ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Electronic Band Structure ◽  
Density Of State ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Zinc Blende

In the present study, ground state and elastic properties of semiconductor MgSe in zinc-blende phase are investigated using density functional theory (DFT). Exchange-correlation potentials are approximated with the generalized gradient approximation (GGA). From the calculated bulk modulus, we determine the refractive index, plasmon energy, cohesive energy and micro-hardness of the MgSe semiconductor binary alloy. The density of state (DOS), projected density of state (PDOS), phonon dispersion frequencies, charged density, electronic band structure and dielectric functions are also reported. From the band structure, a direct band gap of 2.50 eV was observed in close agreement with other reported calculations, but lower than the experimental value of 3.60 eV. Along the high symmetries directions, we found a striking resemblance between MgSe and a III–V semiconductor, while the high cohesive energy in MgSe suggests filled bonding orbitals which might result in decrease in atomic volume with corresponding increased compression of the s-orbitals under any transition series.

ELECTRONIC STRUCTURE, DIELECTRIC AND DYNAMICAL PROPERTIES OF ZINC-BLENDE AlN FROM FIRST PRINCIPLES CALCULATION

2007 ◽  
Vol 21 (26) ◽  
pp. 1775-1784
Author(s):  
HUAN-YOU WANG ◽  
HUI XU ◽  
JIAN-RONG XIAO ◽  
MINGJUN LI
Keyword(s):  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Lattice Parameter ◽  
First Principles Calculation ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Plane Wave Method ◽  
Zinc Blende

We have performed density-functional perturbation calculation for zinc-blende AlN using the pseudopotential plane-wave method. The results obtained using both the local-density approximate (LDA) and the generalized-gradient approximate (GGA) for exchange-correlation functional are compared. The ground state properties and response function properties for zinc-blende AlN , including the electronic band structure, charge density, Born effective charge, dielectric constant and vibrational properties are reported. Our results are basically in agreement with experimental data and theoretical values available, but the bandgap is underestimated and the first optical mode in the phonon band structure is overestimated. This can be attributed to the underestimation of the lattice parameter and selection of the pseudopotential.

scholarly journals Superconductivity in Diamond-like BC3 Phase

2010 ◽  
Vol 2 (2) ◽  
pp. 203-213 ◽  
Author(s):  
M. M. Ali ◽  
A.K.M. A. Islam ◽  
M. Aftabuzzaman ◽  
F. Parvin
Keyword(s):  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Density Functional Method ◽  
Metallic Phase ◽  
Tetragonal Symmetry ◽  
Phonon Coupling ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Electron Phonon Coupling

Two possible phases of superhard material BC3 originating from the cubic diamond structure are investigated by ab initio pseudopotential density functional method using generalized gradient approximation (GGA). We calculate their elastic constants, electronic band structure, and density of states (DOS). Full phonon frequencies, electron-phonon coupling constant and possible superconducting Tc of the metallic phase with tetragonal symmetry (t-BC3, space group P-42m) have for the first time been investigated at 5 and 10 GPa. The calculated electron-phonon coupling (0.67) and the logarithmically-averaged frequency (862 cm-1) show superconductivity for the undoped t-BC3 with Tc = 20 K at 5 GPa, which decreases to 17.5 K at 10 GPa. Keywords: Superhard BC3; Band structure; Phonon spectra; Superconductivity. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.DOI: 10.3329/jsr.v2i2.2638               J. Sci. Res. 2 (2), 203-213 (2010)     

The electronic band structure of silicon

Physica ◽  
1954 ◽  
Vol 3 (7-12) ◽  
pp. 967-970
Author(s):  
D JENKINS
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Electronic Band

THE ELECTRONIC BAND STRUCTURE OF V3Ga AND V3Si

1972 ◽  
Vol 33 (C3) ◽  
pp. C3-223-C3-233 ◽  
Author(s):  
I. B. GOLDBERG ◽  
M. WEGER
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Electronic Band
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