Theoretical investigations of the structural, electronic and optical properties of Hg1−xCdxS alloys

2016 ◽  
Vol 30 (11) ◽  
pp. 1650173 ◽  
Author(s):  
S. Al-Rajoub ◽  
B. Hamad
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Local Density ◽  
Ternary Alloys ◽  
Full Potential ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Electronic And Optical Properties ◽  
Lattice Constants ◽  
Theoretical Investigations

The structural, electronic and optical properties of mercury cadmium sulfide (Hg[Formula: see text]Cd[Formula: see text]S) alloys with [Formula: see text] = 0.0, 0.25, 0.5, 0.75 are studied using density functional theory (DFT) within full-potential linearized augmented plane wave (FPLAPW) method. We used the local density approximation (LDA), the generalized gradient approximation (GGA), Hubbard-corrected functionals (GGA/LDA[Formula: see text]+[Formula: see text][Formula: see text]) and the modified Becke–Johnson (LDA/GGA)-mjb hybrid potentials to treat the exchange-correlation functional [Formula: see text]. We found that LDA functional predicts better lattice constants than GGA functional. Mercury sulfide (HgS) binary alloy was found to exhibit a semi-metallic behavior using all functional with an inverted band gap close to the experimental value. However, the hybrid functionals were more successful than LDA and GGA functionals to predict the correct electronic structure of Hg[Formula: see text]Cd[Formula: see text]S ternary alloys. The results of the electronic and optical band gaps are consistent for Hg[Formula: see text]Cd[Formula: see text]S ternary alloys.

First principles calculations of structural, electronic and optical properties of InN compound

2015 ◽  
Vol 29 (05) ◽  
pp. 1550028 ◽  
Author(s):  
R. Graine ◽  
R. Chemam ◽  
F. Z. Gasmi ◽  
R. Nouri ◽  
H. Meradji ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Local Density ◽  
Indium Nitride ◽  
Alternative Form ◽  
Full Potential ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Electronic And Optical Properties

We carried out ab initio calculations of structural, electronic and optical properties of Indium nitride ( InN ) compound in both zinc blende and wurtzite phases, using the full-potential linearized augmented plane wave method (FP-LAPW), within the framework of density functional theory (DFT). For the exchange and correlation potential, local density approximation (LDA) and generalized gradient approximation (GGA) were used. Moreover, the alternative form of GGA proposed by Engel and Vosko (EV-GGA) and modified Becke–Johnson schemes (mBJ) were also applied for band structure calculations. Ground state properties such as lattice parameter, bulk modulus and its pressure derivative are calculated. Results obtained for band structure of these compounds have been compared with experimental results as well as other first principle computations. Our results show good agreement with the available data. The calculated band structure shows a direct band gap Γ → Γ. In the optical properties section, several optical quantities are investigated; in particular we have deduced the interband transitions from the imaginary part of the dielectric function.

Structural Electronic and Optical Properties of MgO, CaO and SrO Binary Compounds: Comparison Study

2016 ◽  
Vol 257 ◽  
pp. 123-126 ◽  
Author(s):  
Salima Labidi ◽  
Jazia Zeroual ◽  
Malika Labidi ◽  
Kalthoum Klaa ◽  
Rachid Bensalem
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Local Density ◽  
Alternative Form ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Optical Dielectric Constant ◽  
Reported Data

First-principles calculations for electronic and optical properties under pressure effect of MgO, SrO and CaO compounds in the cubic structure, using a full relativistic version of the full-potential augmented plane-wave (FP-LAPW) method based on density functional theory, within the local density approximation (LDA) and the generalized gradient approximation (GGA), have been reported. Furthermore, band structure calculations have been investigated by the alternative form of GGA proposed by Engel and Vosko (GGA-EV) and modified by Becke-Johnson exchange correlation potential (MBJ-GGA). All calculated equilibrium lattices, bulk modulus and band gap at zero pressure are find in good agreement with the available reported data. The pressure dependence of band gap and the static optical dielectric constant are also investigated in this work.

scholarly journals Prediction of electronic and optical properties for Zn1-xCdxSeyTe1-y quaternary alloys: First-principles study

2021 ◽  
Vol 67 (4 Jul-Aug) ◽  
pp. 041001
Author(s):  
K. Benchikh ◽  
M. Benchehima ◽  
H. A. Bid ◽  
A. Chabane Chaouche
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Local Density ◽  
Quaternary Alloy ◽  
Full Potential ◽  
Generalized Gradient ◽  
Quaternary Alloys ◽  
Electronic And Optical Properties ◽  
The Density Functional Theory

In the present work, the density functional theory (DFT) was performed for the investigation of the structural, electronic and optical properties of the Zn1-xCdxSeyTe1-y quaternary alloys using the full potential linearized augmented plane wave (FP-LAPW) method. For the calculations of the structural properties we have used the Perdew-Burke-Ernzerhof generalized gradient approximation (GGA-PBEsol). On other hand, the electronic properties have been computed within the local density approximation (LDA) in adding to the Tran-Blaha modified Becker-Johnson (TB-mBJ) approach. Our results indicate that the lattice constant, as well as the bulk modulus and the energy gap for the Zn1-xCdxSeyTe1-y quaternary show almost linear variations on the concentration x (0.125≤x≤0.875). In addition, the simulated band structures for theZn1-xCdxSeyTe1-y quaternary exhibits a direct-gap for all concentrations. Moreover, low bowing parameters are observed. Also, some interesting optical properties such as dielectric constant, refractive index, extinction coefficient, absorption coefficient and reflectivity have been calculated by using the TB-mBJ method.  The results of our computations shows that theZn1-xCdxSeyTe1-y quaternary alloy is a promissing candidate for optoelectronic applications. It is noteworthy that the present work is the first theoretical study of the quaternary of interest using the FP-LAPW calculations.

DFT-BASEDAB INITIOSTUDY OF THE ELECTRONIC AND OPTICAL PROPERTIES OF CESIUM BASED FLUORO-PEROVSKITECsMF3(M = CaANDSr)

2012 ◽  
Vol 26 (32) ◽  
pp. 1250199 ◽  
Author(s):  
M. HARMEL ◽  
H. KHACHAI ◽  
M. AMERI ◽  
R. KHENATA ◽  
N. BAKI ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Theoretical Data ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Structure Density

Density functional theory (DFT) is performed to study the structural, electronic and optical properties of cubic fluoroperovskite AMF3( A = Cs ; M = Ca and Sr ) compounds. The calculations are based on the total-energy calculations within the full-potential linearized augmented plane wave (FP-LAPW) method. The exchange-correlation potential is treated by local density approximation (LDA) and generalized gradient approximation (GGA). The structural properties, including lattice constants, bulk modulus and their pressure derivatives are in very good agreement with the available experimental and theoretical data. The calculations of the electronic band structure, density of states and charge density reveal that compounds are both ionic insulators. The optical properties (namely: the real and the imaginary parts of the dielectric function ε(ω), the refractive index n(ω) and the extinction coefficient k(ω)) were calculated for radiation up to 40.0 eV.

AB INITIO STUDY OF STRUCTURAL, ELECTRONIC AND OPTICAL PROPERTIES OF MgxCd1-xX (X = S, Se, Te) ALLOYS

2012 ◽  
Vol 26 (30) ◽  
pp. 1250168 ◽  
Author(s):  
N. A. NOOR ◽  
A. SHAUKAT
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Ternary Alloys ◽  
Full Potential ◽  
Generalized Gradient ◽  
Calculated Density ◽  
Electronic And Optical Properties ◽  
Direct Band

This study describes structural, electronic and optical properties of Mg x Cd 1-x X (X = S, Se, Te) alloys in the complete range 0≤x ≤1 of composition x in the zinc-blende (ZB) phase with the help of full-potential linearized augmented plane wave plus local orbitals (FP-LAPW+lo) method within density functional theory (DFT). In order to calculate total energy, generalized gradient approximation (Wu–Cohen GGA) has been applied, which is based on optimization energy. For electronic structure calculations, the corresponding potential is being optimized by Engel–Vosko GGA formalism. Our calculations reveal the nonlinear variation of lattice constant and bulk modulus with different concentration for the end binary and their ternary alloys, which slightly deviates from Vegard's law. The calculated band structures show a direct band gap for all three alloys with increasing order in the complete range of the compositional parameter x. In addition, we have discussed the disorder parameter (gap bowing) and concluded that the total band gap bowing is substantially influenced by the chemical (electronegativity) contribution. The calculated density of states (DOS) of these alloys is discussed in terms of contribution from various s-, p- and d-states of the constituent atoms and charge density distributions plots are analyzed. Optical properties have been presented in the form of the complex dielectric function ε(ω), refractive index n(ω) and extinction coefficient k(ω) as function of the incident photon energy, and the results have been compared with existing experimental data and other theoretical calculations.

THEORETICAL INVESTIGATIONS OF β-TRICALCIUM PHOSPHATE BIOMATERIALS: DFT INSIGHT

2016 ◽  
Vol 78 (3-2) ◽  
Author(s):  
A. M. A. Bakheet ◽  
M. A. Saeed ◽  
A. R. M. Isa ◽  
R. Sahnoun
Keyword(s):  
Optical Properties ◽  
Calcium Phosphate ◽  
Density Functional ◽  
Local Density ◽  
Ionic Character ◽  
Chemical Compositions ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Dental Applications

Beta-tri-calcium phosphate (β-TCP) materials have gained a great deal of research considerations in biomaterial area due to their excellent biocompatibility and identical chemical compositions to the natural teeth and bones. Therefore, the β-TCP compound can be used as coatings, cement and composites as well as biocompatible ceramics for medical and dental applications. Electronic and optical properties for β-TCP compound have been investigated using density functional theory (DFT). For the calculations, we used full potential linear augmented plane wave method (FPLAPW), within three types of approximations along with local density approximations (LDA), generalized gradient approximations (GGA) and Modified Becke-Johnson (mBJ) to get the effect of the exchange and correlation in our calculations to get an accurate results. The computed band gap values for (β-TCP) compound using LDA, GGA, and mBJ-GGA approximations are 5.5 eV, 5.9 eV and 6.8 eV respectively. This is also predicted that the chemical bonding in this compound is a kind of combination of covalent and ionic character that is in a line with the experimental findings. The optical parameter, static dielectric constant ε1(0) reaches the values of 3.23681 (eV) at 0 GPa for the β-TCP compound. The obtained results are of vital nature for rising the quality of the electronic and optical properties of this material, and provide more evidence to fabricate novel Beta-Tri-calcium phosphate biomaterials for medical and dental applications.

STRUCTURAL, ELECTRONIC AND OPTICAL PROPERTIES OF MgSxSe1-x, MgSxTe1-x AND MgSexTe1-x (0 ≤x ≤1) ALLOYS FROM FIRST PRINCIPLES

2012 ◽  
Vol 26 (17) ◽  
pp. 1250098 ◽  
Author(s):  
A. SAJID ◽  
S. M. ALAY-E-ABBAS ◽  
A. AFAQ ◽  
A. SHAUKAT
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Structural Parameters ◽  
Ternary Alloys ◽  
Full Potential ◽  
Generalized Gradient ◽  
Volume Deformation ◽  
Electronic Band ◽  
Electronic And Optical Properties

First principles total energy calculations have been performed using full potential linear augmented plane wave method (FP-LAPW) within density functional theory to study the structural, electronic and optical properties of MgS x Se 1-x, MgS x Te 1-x and MgSe x Te 1-x alloys in the rock salt crystallographic phase. The generalized gradient approximation parameterization scheme has been used for calculating the ground state structural parameters and their deviation from the Vegard's law has been discussed. Full relativistic electronic band structures and density of states have been calculated to study the electronic properties of the end binary compounds and ternary alloys MgS x Se 1-x, MgS x Te 1-x and MgSe x Te 1-x (0.25 < x < 0.75). Optical bowing for these semiconductor alloys has been discussed in term of volume deformation, electronegativity and structural relaxation. Optical properties of the binary and ternary magnesium chalcogenides have been calculated in terms of the complex dielectric function and the results are compared with available theoretical and experimental data.

First-principles investigation of the structural, elastic, electronic, and optical properties of semiconducting AgBr1–xIx (0 ≤ x ≤ 1) ternary alloys in rock-salt and zinc blende structures

2020 ◽  
Vol 98 (9) ◽  
pp. 834-848
Author(s):  
H. Rekab-Djabri ◽  
Mohamed Drief ◽  
Manal M. Abdus Salam ◽  
Salah Daoud ◽  
F. El Haj Hassan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Rock Salt ◽  
Density Functional ◽  
Local Density ◽  
Ternary Alloys ◽  
Full Potential ◽  
Zinc Blende ◽  
Lmto Method ◽  
Direct Band

In this work, first principle calculations of the structural, electronic, elastic, and optical properties of novel AgBr1–xIx ternary alloys in rock-salt (B1) and zinc-blende (B3) structures are presented. The calculations were performed using the full-potential linear muffin-tin orbital (FP-LMTO) method within the framework of the density functional theory (DFT). The exchange and correlation potentials were treated according to the local density approximation (LDA). The lattice constants for the B1 and B3 phases versus iodide concentration (x) were found to deviate slightly from the linear relationship of Vegard’s law. The calculated electronic properties showed that AgBr1–xIx alloys in the B3 structure have a direct band gap (Γ – Γ) for all concentrations of x, which means that they can be used in long-wavelength optoelectronic applications, while in the B1 structure they have an indirect (Γ – R) band gap. The elastic constants Cij, shear modulus G, Young’s modulus E, Poisson’s ratio ν, index of ductility B/G, sound velocities vt, vl, and vm, and Debye temperature θD were also reported and analyzed. By incorporating the basic optical properties, we discussed the dielectric function, refractive index, optical reflectivity, absorption coefficient, and optical conductivity in terms of incident photon energy up to 13.5 eV. The present results were found to be in good agreement with the available experimental and other theoretical results.

First principle investigations of the optical properties of Zn1-xMgxS, Zn1-xMgxSe and Zn1-xMgxTe ternary alloys

2014 ◽  
Vol 28 (31) ◽  
pp. 1450221 ◽  
Author(s):  
M. Dadsetani ◽  
A. Zeinivand
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Random Phase ◽  
Ternary Alloys ◽  
Optical Absorption Coefficient ◽  
Full Potential ◽  
Generalized Gradient ◽  
The Density Functional Theory ◽  
Ternary Semiconductor

Optical properties of Zn 1-x Mg x S , Zn 1-x Mg x Se and Zn 1-x Mg x Te (0 ≤ x ≤ 1) ternary semiconductor alloys are calculated using the full potential linearized augmented plane wave within the density functional theory. The exchange correlation potential is treated by the generalized gradient approximation (GGA) within Perdew et al. scheme. The real and imaginary parts of the dielectric function ε(ω), the refractive index n(ω), the extinction coefficient k(ω), the optical absorption coefficient α(ω), the reflectivity R(ω) and the electron energy loss function (EELS) are calculated within random phase approximation (RPA). Our results are compared with the previous theoretical calculations and available experimental data. Moreover, the interband transitions responsible for the structures seen in the spectra are specified. It is shown that, the chalcogen p states as initial and Zn 4s, Mg 3s, chalcogen d states as final states perform the major role in optical transitions.

Investigation of the structural, electronic, elastic and thermodynamic properties of Curium Monopnictides: An ab initio study

2017 ◽  
Vol 31 (30) ◽  
pp. 1750226 ◽  
Author(s):  
H. Baaziz ◽  
Dj. Guendouz ◽  
Z. Charifi ◽  
S. Akbudak ◽  
G. Uğur ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
Density Functional ◽  
Local Density ◽  
Structural Parameters ◽  
Structural Phase ◽  
Full Potential ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Spin Polarized

The structural, electronic, elastic and thermodynamic properties of Curium Monopnictides CmX (X = N, P, As, Sb and Bi) are investigated using first-principles calculations based on the density functional theory (DFT) and full potential linearized augmented plane wave (FP-LAPW) method under ambient condition and high pressure. The exchange-correlation term is treated using two approximations spin-polarized local density approximation (LSDA) and spin-polarized generalized gradient approximation generalized (GGA). The structural parameters such as the equilibrium lattice parameters, bulk modulus and the total energies are calculated in two phases: namely NaCl (B1) and CsCl (B2). The obtained results are compared with the previous theoretical and experimental results. A structural phase transition from B1 phase to B2 phase for Curium pnictides has been obtained. The highest transition pressure is 122 GPa for CmN and the lowest one is 10.0 GPa for CmBi compound. The electronic properties show that these materials exhibit half-metallic behavior in both phases. The magnetic moment is found to be around 7.0 [Formula: see text]B. The mechanical properties of CmX (X = N, P, As, Sb and Bi) are predicted from the calculated elastic constants. Our calculated results are in good agreement with the theoretical results in literature. The effect of pressure and temperature on the thermodynamic properties like the cell volume, bulk modulus and the specific heats C[Formula: see text] and C[Formula: see text], the entropy [Formula: see text] and the Grüneisen parameter [Formula: see text] have been foreseen at expanded pressure and temperature ranges.

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