scholarly journals Theoretical Prediction of Lanthanum Composition Effects on Structural, Electronic and Thermal Properties of LaxSc1-XN Alloys.

2021 ◽  
Author(s):  
Amira EL-HASSASNA ◽  
CHAOUCHE Yassine ◽  
Louafi Ahd
Keyword(s):  
Thermal Properties ◽  
Density Functional ◽  
Correlation Energy ◽  
Small Deviation ◽  
Debye Model ◽  
Ternary Alloys ◽  
Full Potential ◽  
Generalized Gradient ◽  
Salt Structure ◽  
Binary Compounds

Abstract In this paper we have study the structural, electronic and thermal properties of LaxSc1−xN ternary alloys in rock-salt structure by the use of full potential linearized augmented plane wave (FP-LAPW) method based to the density functional theory (DFT). For calculate the exchange-correlation energy and potential we are used both the Wu-Cohen generalized gradient (WC-GGA) approximation and the modified Becke-Johnson(mBJ).We investigated the fact of composition on lattice parameters, bulk modulus and band gap. The variation of calculated lattice constant with lanthanum composition is almost linear and shows a small deviation of the obtained results from Vegard’s law. The semiconductor nature of binary compounds ScN and LaN was confirmed. Our finding indicates that the LaxSc1−xN alloys are semiconductor with x = 0.5 and 0.75, on the contrary for x = 0.25 has a metallic nature. Lastly, the effect of thermal macroscopic properties is also investigated employing the quasi-harmonic Debye model in which the lattice vibrations are taken into account. We have found a good accord between our results and the experimental data and previous theoretical results available in the literature for the binary compounds which can be a support for the ternary alloys in the future.

First-principles calculations of structural, electronic and thermal properties of Zn1−x MgxS ternary alloys

Open Physics ◽  
2014 ◽  
Vol 12 (1) ◽  
Author(s):  
Samia Lamraoui ◽  
Rachid Bensalem ◽  
Khadidja Hacini ◽  
Hocine Meradji ◽  
Sebti Ghemid ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Density Functional ◽  
Small Deviation ◽  
Experimental Studies ◽  
Theoretical Data ◽  
Debye Model ◽  
Ternary Alloys ◽  
Full Potential ◽  
Generalized Gradient ◽  
Vegard’S Law

AbstractStructural, electronic and thermal properties of Zn1−x MgxS ternary alloys are studied by using the full potential-linearized augmented plane wave method (FP-LAPW) within the density functional theory (DFT). The Wu-Cohen generalized gradient approximation (WC-GGA) is used in this approach for the exchangecorrelation potential. Moreover, the modified Becke-Johnson approximation (mBJ) is adopted for band structure calculations. The dependence of the lattice constant, bulk modulus and band gap on the composition x showed that the first exhibits a small deviation from the Vegard’s law, whereas, a marginal deviation of the second from linear concentration dependence (LCD). The bowing of the fundamental gap versus composition predicted by our calculations agrees well with the available theoretical data. The microscopic origins of the gap bowing are explained by using the approach of Zunger and co-workers. Thermal effects on some macroscopic properties of Zn1−x MgxS alloys are also investigated using the quasi-harmonic Debye model, in which the phononic effects are considered. As, this is the first quantitative theoretical prediction of the thermal properties of Zn1−x MgxS alloys, no other calculated results and furthermore no experimental studies are available for comparison.

FIRST PRINCIPLES CALCULATIONS OF STRUCTURAL, ELECTRONIC, THERMODYNAMIC AND THERMAL PROPERTIES OF BaxSr1-xTe TERNARY ALLOYS

2014 ◽  
Vol 28 (04) ◽  
pp. 1450041
Author(s):  
S. CHELLI ◽  
H. MERADJI ◽  
S. AMARA KORBA ◽  
S. GHEMID ◽  
F. EL HAJ HASSAN
Keyword(s):  
Thermal Properties ◽  
Bulk Modulus ◽  
Band Gap ◽  
Lattice Constant ◽  
Density Functional ◽  
Enthalpy Of Mixing ◽  
Mixed Crystals ◽  
Ternary Alloys ◽  
Full Potential ◽  
Generalized Gradient

The structural, electronic thermodynamic and thermal properties of Ba x Sr 1-x Te ternary mixed crystals have been studied using the ab initio full-potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). In this approach, the Perdew–Burke–Ernzerhof-generalized gradient approximation (PBE-GGA) was used for the exchange-correlation potential. Moreover, the recently proposed modified Becke Johnson (mBJ) potential approximation, which successfully corrects the band-gap problem was also used for band structure calculations. The ground-state properties are determined for the cubic bulk materials BaTe , SrTe and their mixed crystals at various concentrations (x = 0.25, 0.5 and 0.75). The effect of composition on lattice constant, bulk modulus and band gap was analyzed. Deviation of the lattice constant from Vegard's law and the bulk modulus from linear concentration dependence (LCD) were observed for the ternary Ba x Sr 1-x Te alloys. The microscopic origins of the gap bowing were explained by using the approach of Zunger and co-workers. On the other hand, the thermodynamic stability of these alloys was investigated by calculating the excess enthalpy of mixing, ΔHm as well as the phase diagram. It was shown that these alloys are stable at high temperature. Thermal effects on some macroscopic properties of Ba x Sr 1-x Te alloys were investigated using the quasi-harmonic Debye model, in which the phononic effects are considered.

scholarly journals First-Principles Predictions on Structural Stability, Electronic, Optical, and Thermal Properties of Semiconductors GaNxAs1-x: Materials for Futuristic Optoelectronic Energy Devices

2021 ◽  
Author(s):  
Souheyla Gagui ◽  
Sebti Ghemid ◽  
Hocine Meradji ◽  
Beddiaf Zaidi ◽  
Bakhtiar Ul Haq ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Phase Stability ◽  
Density Functional ◽  
Debye Model ◽  
Ternary Alloys ◽  
Full Potential ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Energy Devices ◽  
Linearized Augmented Plane Wave

Abstract The knowledge of the physical properties of a material is crucial to realize its practical technological applications.Here, a study related to phase stability, transition pressure, electronic, optical,and thermal propertiesof GaAs, GaN, as well as their mixed ternary alloys GaN0.25As0.75, GaN0.5As0.5, andGaN0.75As0.25 is presented. The study is performed by employing "full-potential linearized augmented-plane-wave plus local-orbital, (FP-L(APW+lo))approach framed within density functional theory (DFT)" and recognized within WIEN2k computational code. The results of the phase stability show that the GaNxAs1-x alloys are stable for all compositions in the zinc blendephase (B3),except for x=1,, whereas the structure corresponding to x=1 composition is found to be more stable inthe wurtzite (B4) phase. The physicalproperties of the more stable phases corresponding to each composition are explored. The pressure-induced phase transition is also investigatedcorresponding to each composition. The electronic and optical properties are investigated using the Tran-Blahamodified Becke-Johnson (mBJ) potential approach. To explore the thermal properties, the "quasi-harmonic Debye model" approach is employed. Our calculated results of the absorption coefficients and optical band gap show that these alloys could be appropriate candidates for applications in solar cell and optoelectronic devices.

STRUCTURAL PROPERTIES OF III-NITRIDE BINARY COMPOUNDS: A COMPREHENSIVE STUDY

2009 ◽  
Vol 23 (08) ◽  
pp. 1111-1127
Author(s):  
RASHID AHMED ◽  
FAZAL-E-ALEEM ◽  
HARIS RASHID ◽  
H. AKBARZADEH ◽  
S. JAVAD HASHEMIFAR
Keyword(s):  
Structural Properties ◽  
Rock Salt ◽  
Density Functional ◽  
Correlation Energy ◽  
Local Density ◽  
Full Potential ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Lattice Constants ◽  
Binary Compounds

Very little information is available about the structural properties of III-nitride binary compounds in the rock-salt phase. We report/review a comprehensive theoretical study of structural properties of these compounds in rock-salt, zinc-blende and wurtzite phases. Calculations have been made using full-potential linearized augmented plane wave plus local orbitals (FP-L(APW+lo)) method as embodied in WIEN2k code framed within density functional theory (DFT). In this approach of calculations, local density approximation (LDA) [J. P. Perdew and Y. Wang, Phys. Rev. B45 (1992) 13244] and generalized gradient approximation (GGA) [J. P. Perdew, K. Burke and M. Ernzerhof, Phys. Rev. Lett.72 (1996) 3865] have been used for exchange-correlation energy and corresponding potential. Calculated results for lattice constants, bulk modulus, its pressure derivative and cohesive energy of these compounds are consistent with the experimental results. Following these calculations, besides many new results for the rock-salt and other phases, a comprehensive review of the structural properties emerges. We also list some peculiar features of these compounds.

Electronic Structure Of (AgSb)xPbn-2xTen

2003 ◽  
Vol 793 ◽  
Author(s):  
Daniel I Bilc ◽  
S.D. Mahanti ◽  
M.G. Kanatzidis
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Density Functional ◽  
Full Potential ◽  
Generalized Gradient ◽  
Two Component System ◽  
Functional Theory ◽  
Covalent Interaction ◽  
Salt Structure ◽  
Linearized Augmented Plane Wave

ABSTRACTComplex quaternary chalcogenides (AgSb)xPbn-2xTen (0<x<n/2) are thought to be narrow band-gap semiconductors which are very good candidates for room and high temperature thermoelectric applications. These systems form in the rock-salt structure similar to the well known two component system PbTe (x=0). In these systems Ag and Sb occupy Pb sites randomly although there is some evidence of short-range order. To gain insights into the electronic structure of these compounds, we have performed electronic structure calculations in AgSbTe2 (x=n/2). These calculations were carried out within ab initio density functional theory (DFT) using full potential linearized augmented plane wave (LAPW) method. The generalized gradient approximation (GGA) was used to treat the exchange and correlation potential. Spinorbit interaction (SOI) was incorporated using a second variational procedure. Since it is difficult to treat disorder in ab initio calculations, we have used several ordered structures for AgSbTe2. All these structures show semimetallic behavior with a pseudogap near the Fermi energy. Te and Sb p orbitals, which are close in energy, hybridize rather strongly indicating a covalent interaction between Te and Sb atoms.

scholarly journals Ab initio calculations of structural, elastic, electronic and thermodynamic properties of the cerium filled skutterudite CeRu4P12 under the effect of pressure

2015 ◽  
Vol 33 (4) ◽  
pp. 699-708 ◽  
Author(s):  
Mokhtar Berrahal ◽  
Mohammed Ameri ◽  
Y. Al-Douri ◽  
U. Hashim ◽  
Dinesh Varshney ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
Density Functional ◽  
Debye Model ◽  
Lattice Parameter ◽  
Full Potential ◽  
Generalized Gradient ◽  
Filled Skutterudite ◽  
Effect Of Pressure ◽  
Lmto Method

AbstractThe paper presents an investigation on crystalline, elastic and electronic structure in addition to the thermodynamic properties for a CeRu4P12 filled skutterudite device by using the full-potential linear muffin-tin orbital (FP-LMTO) method within the generalized gradient approximations (GGA) in the frame of density functional theory (DFT). For this purpose, the structural properties, such as the equilibrium lattice parameter, bulk modulus and pressure derivatives of the bulk modulus, were computed. By using the total energy variation as a function of strain we have determined the independent elastic constants and their pressure dependence. Additionally, the effect of pressure P and temperature T on the lattice parameters, bulk modulus, thermal expansion coefficient, Debye temperature and the heat capacity for CeRu4P12 compound were investigated taking into consideration the quasi-harmonic Debye model.

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.

scholarly journals Ab initio studies of structural, electronic, optical, elastic and thermal properties of CuGaTe-=SUB=-2-=/SUB=-

2017 ◽  
Vol 51 (5) ◽  
pp. 711
Author(s):  
Pravesh Singh ◽  
Sheetal Sharma ◽  
Sarita Kumari ◽  
Vibhav K Saraswat ◽  
D. Sharma ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Ab Initio ◽  
Density Functional ◽  
Structural Parameters ◽  
Debye Model ◽  
Full Potential ◽  
Augmented Plane Wave ◽  
Different Temperatures ◽  
First Time ◽  
Linearized Augmented Plane Wave

We have performed ab initio calculations for the structural, electronic, optical, elastic and thermal properties of CuGaTe2. In this study, we used an accurate full potential linearized augmented plane wave (FP-LAPW) method to find the equilibrium structural parameters and to compute the full elastic tensors. We report electronic and optical properties with the recently developed density functional of Tran and Blaha. Furthermore, optical features such as dielectric functions, refractive indices, extinction coefficient, optical reflectivity, absorption coefficients, optical conductivities, were calculated for photon energies up to 30 eV. The thermodynamical properties such as Debye temperature, entropy and Gruneisen parameter, bulk modulus and hardness were calculated employing the quasi-harmonic Debye model at different temperatures (0-1000 K) and pressures (0-8 GPa) and the silent results were interpreted. Most of the investigated parameters are reported for the first time. DOI: 10.21883/FTP.2017.05.44433.8044

First-principles calculations to investigate structural, electronic and optical properties of (ZnSe)n/(ZnTe)n superlattices

2020 ◽  
Author(s):  
Messaoud Caid
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Correlation Energy ◽  
Local Density ◽  
Full Potential ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Lmto Method ◽  
Binary Compounds

An investigation into the structural, electronic and optical properties of superlattices(SLs) (ZnSe)n/(ZnTe)n was conducted using first principles calculations based on density functional theory (DFT). The total energies were calculated within the full-potential linear muffin-tin orbital (FP-LMTO) method augmented by a plane-wave basis (PLW), implemented in LmtART 7.0 code. The effects of the approximations to the exchange-correlation energy were treated by the local density approximation (LDA). The ground state properties of (ZnSe)n/(ZnTe)n binary compounds are determined and compared with the available data. It is found that the superlattice (n-n: 1-1, 2-2 and 3-3) band gaps vary depending on the layers used. The optical constants, including the dielectric function ε(w), the refractive index n(w) and the reflectivity R(w), are calculated for radiation energies up to 35eV.

Structural, electronic and magnetic properties of Ru2CrGe and Ru2MnGe: FP-LAPW calculations

2015 ◽  
Vol 29 (18) ◽  
pp. 1550093 ◽  
Author(s):  
Zineb Aarizou ◽  
Soumia Bahlouli ◽  
Mokhtar Elchikh
Keyword(s):  
Magnetic Properties ◽  
Correlation Energy ◽  
Heusler Alloys ◽  
Energy Difference ◽  
Field Approximation ◽  
Debye Model ◽  
Mean Field Approximation ◽  
Full Potential ◽  
Generalized Gradient ◽  
First Principle Calculation

Structural and magnetic properties as well as the electronic structures of [Formula: see text] Heusler alloys were investigated in the framework of first principle calculation. Using the full-potential linearized augmented plane wave (FP-LAPW) in connection with the generalized gradient approximation (GGA) treatment of exchange-correlation energy, we have performed the structural optimization in the non-magnetic (NM) and three different magnetic configurations: FM, AFM-I and AFM-II. We have found that our two compounds are stable for the AFM-II state, which agree with the available experimental and theoretical results. The exchange constants [Formula: see text] and [Formula: see text] as well as the temperature of transition to the paramagnetic state [Formula: see text] were estimated here by the use of the energy difference method and the mean field approximation. The electronic structure of our compounds in their magnetic state was also studied. The GGA [Formula: see text]+ [Formula: see text]U method has also been used to take into account the strong correlations among the d orbitals of [Formula: see text] and [Formula: see text] atoms. This has considerably improved both the electronic and magnetic results which became close to the corresponding experimental data. We have finally studied the thermodynamic properties using the quasi-harmonic Debye model as implemented in the Gibbs Program.

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