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.

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.

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 Study of Structural, Electronic, Optical and Elastic Properties of Cadmium Based Fluoro-Perovskite MCdF3 (M= Rb, Tl)

2019 ◽  
Vol 297 ◽  
pp. 173-186 ◽  
Author(s):  
Abderrahmane Cheriet ◽  
Brahim Lagoun ◽  
Mohamed Halit ◽  
Mourad Zaabat ◽  
Chadli Abdelhakim ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Local Density ◽  
Poisson Ratio ◽  
Exchange Potential ◽  
Full Potential ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Conduction Bands

This paper presents a theoretical study using the full potential linearized augmented plane wave approach (FP-LAPW) based on the density functional theory (DFT) to predict the structural and electronic properties of RbCdF3 and TlCdF3 compounds. The exchange-correlation potential is treated by the local density approximation (LDA), generalized gradient approximation (GGA) and modified Beck-Johnson exchange potential (mBJ). The calculated structural properties such as the equilibrium lattice parameter, the bulk modulus and its pressure derivative are in good agreement with the available data. The obtained results for the band structure and the density of states (DOS) show that the RbCdF3 (TlCdF3) compound have an indirect band gap of 6.77 and 3.07 eV (5.70 and 3.66 eV) with TB-mBJ and WC method respectively. From the electronic transition from valence conduction bands to conduction bands the optical properties were calculated. The elastic constants were calculated using the energy deformation relationship, from these constants the other mechanical properties such as bulk modulus, shear modulus, Young modulus and Poisson ratio were calculate and comment. Lastly, the elastic anisotropy was discussed.

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.

Density Functional Study of the Structural Properties of Copper Iodide: LDA vs GGA Calculations

2009 ◽  
Vol 5 ◽  
pp. 25-30 ◽  
Author(s):  
Heribert Hernández-Cocoletzi ◽  
Gregorio H. Cocoletzi ◽  
J.F. Rivas-Silva ◽  
A. Flores ◽  
Noboru Takeuchi
Keyword(s):  
Structural Properties ◽  
Ground State ◽  
Density Functional ◽  
Local Density ◽  
Structural Parameters ◽  
External Pressure ◽  
Functional Study ◽  
Full Potential ◽  
Copper Iodide ◽  
Generalized Gradient

We have performed first principles total energy calculations to investigate the structural properties of copper iodide (CuI) in its sodium chloride, cesium chloride, zincblende and wurtzite structures. Calculations are done using the density functional theory. We employ the full potential linearized augmented plane wave method as implemented in the wien2k code. The exchange and correlation potential energies are treated in the generalized gradient approximation (GGA), and the local density approximation (LDA). Optical absorption experiments and x-ray diffraction measurements have shown that zincblende is the ground state of CuI. Our calculations find that in the GGA formalism wurtzite and zincblende have similar total energies, while in the LDA formalism the lowest minimum corresponds to zincblende. Results show that the energy difference between the wurtzite and the zincblende structures, as calculated within the GGA formalism is 2 meV, and within the LDA formalism, is 31 meV. These results may suggest a coexistence of both wurtzite and zincblende structures in the ground state of CuI. Structural parameters are correctly reproduced by the GGA calculations. We obtain that under the application of external pressure the atomic configuration may transform into the NaCl structure. At higher pressures it is possible to have a phase transition to the CsCl geometry.

Density functional study of the structural and phase transition of silver halides: LDA versus GGA calculations

2019 ◽  
Vol 08 (02) ◽  
pp. 1950006 ◽  
Author(s):  
H. Rekab Djabri ◽  
R. Yagoub ◽  
S. Bahlouli ◽  
S. Amari ◽  
S. Louhibi Fasla
Keyword(s):  
Phase Transition ◽  
Density Functional ◽  
Local Density ◽  
Structural Phase ◽  
Lattice Parameter ◽  
Functional Study ◽  
Full Potential ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Structural And Electronic Properties

This paper deals with the theoretical calculation of structural and electronic, properties of AgBr and AgCl compounds using density functional theory within generalized-gradient (GGA) approximation and local density approximation (LDA). We employ the full potential linear muffin-tin orbitals (FP-LMTO) as implemented in the Lmtart code. We have used to examine structure parameter in eight different structures such as in NaCl (B1), CsCl (B2), ZB (B3), NiAs (B8), PbO (B10), Wurtzite (B4), HCP (A3) [Formula: see text]Sn (A5) structures. The equilibrium lattice parameter, bulk modulus and its pressure derivative were presented for all calculated phases. The calculated ground state properties are in good agreement with available experimental and theoretical results. A pressure induced structural phase transition from NaCl (B1) to HCP (A3) phases at 37.66 and 18.11[Formula: see text]GPa for AgBr and AgCl, respectively, and from NaCl to CsCl phase in AgBr and AgCl at 90.55 and 24.4[Formula: see text]GPa, respectively, is also predicted. Furthermore, the band structures are computed. Our results are compared to other theoretical and experimental works, and excellent agreement is obtained.

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.

Density Functional Theory Approach for Muon Sites Estimation in Mn3Sn

2021 ◽  
Vol 1028 ◽  
pp. 199-203
Author(s):  
Fiqhri Heda Murdaka ◽  
Edi Suprayoga ◽  
Abdul Muizz Pradipto ◽  
Kohji Nakamura ◽  
Agustinus Agung Nugroho
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Local Density ◽  
Full Potential ◽  
Theory Approach ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electrostatic Potential Calculation ◽  
A Site ◽  
Linearized Augmented Plane Wave

We report the estimation of muon sites inside Mn3Sn using density functional theory based on the full-potential linearized augmented plane wave (FLAPW) calculation. Our calculation shows that the Perdew–Burke–Ernzerhof (PBE) Generalized-Gradient Approximation (GGA) functional is closer to the experimental structure compared to the von Barth-Hedin Local Density Approximation (LDA)-optimized geometry. The PBE GGA is therefore subsequently used in FLAPW post-calculation for the electrostatic potential calculation to find the local minima position as a guiding strategy for estimating the muon site. Our result reveals at least two muon sites of which one is placed at the center between two Mn-Sn triangular layers (A site) and the other at the trigonal prismatic site of Sn atom (B site). The total energy of Mn3Sn system in the presence of muon at A site or B site are compared and we find that A site is a more favorable site for muon to stop.

Structural, electronic and elastic properties of the B2-ScM (M =Au, Hg and Tl) intermetallic compounds: Ab initio calculations

2015 ◽  
Vol 04 (04) ◽  
pp. 1550020
Author(s):  
Ahmad A. Mousa ◽  
Jamil M. Khalifeh
Keyword(s):  
Mechanical Properties ◽  
Bulk Modulus ◽  
Intermetallic Compounds ◽  
Elastic Constants ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic Band

Structural, electronic, elastic and mechanical properties of ScM (M[Formula: see text][Formula: see text][Formula: see text]Au, Hg and Tl) intermetallic compounds are studied using the full potential-linearized augmented plane wave (FP-LAPW) method based on the density functional theory (DFT), within the generalized gradient approximation (GGA) and the local density approximation (LDA) to the exchange-correlation approximation energy as implemented in the Wien2k code. The ground state properties including lattice parameters, bulk modulus and elastic constants were all computed and compared with the available previous theoretical and experimental results. The lattice constant was found to increase in contrast to the bulk modulus which was found to decrease with every substitution of the cation (M) starting from Au till Tl in ScM. Both the electronic band structure and density-of-states (DOS) calculations show that these compounds possess metallic properties. The calculated elastic constants ([Formula: see text], [Formula: see text] and [Formula: see text] confirmed the elastic stability of the ScM compounds in the B2-phase. The mechanical properties and ductile behaviors of these compounds are also predicted based on the calculated elastic constants.

AB INITIO STUDY OF PHONON DISPERSION AND ELASTIC PROPERTIES OF L12 INTERMETALLICS Ti3Al AND Y3Al

2013 ◽  
Vol 27 (30) ◽  
pp. 1350224 ◽  
Author(s):  
N. ARIKAN ◽  
M. ERSEN ◽  
H. Y. OCAK ◽  
A. İYIGÖR ◽  
A. CANDAN ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Phonon Dispersion ◽  
High Symmetry ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Phonon Dispersion Curves ◽  
Lattice Constants ◽  
Density Functional Perturbation Theory ◽  
Phonon Properties

In this paper, the structural, elastic and phonon properties of Ti 3 Al and Y 3 Al in L1 2( Cu 3 Al ) phase are studied by performing first-principles calculations within the generalized gradient approximation. The calculated lattice constants, static bulk moduli, first-order pressure derivative of bulk moduli and elastic constants for both compounds are reported. The phonon dispersion curves along several high-symmetry lines at the Brillouin zone, together with the corresponding phonon density of states, are determined using the first-principles linear-response approach of the density functional perturbation theory. Temperature variations of specific heat in the range of 0–500 K are obtained using the quasi-harmonic model.

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