scholarly journals Structural Optimization and the Study of the Electronic, Mechanical, Thermodynamic and Phonon Properties of Mg2sn from First Principle

2020 ◽  
pp. 60-71
Author(s):  
I. S. Okunzuwa ◽  
E. Aigbekaen, Eddy ◽  
T. Philips Chidubem
Keyword(s):  
Density Functional ◽  
Phonon Dispersion ◽  
Young Modulus ◽  
Computer Code ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Optical Branch ◽  
Cauchy Pressure ◽  
Phonon Properties ◽  
Good Agreement

First principles pseudopotential method based on density functional theory is used to investigate the Structural, Mechanical, Phonon, Thermodynamic and Electronic properties of Mg2Sn. The equilibrium properties including lattice constant, bulk modulus, pressure derivative cohesive energy, young modulus, shear modulus were determined. The results obtained were compared with available experimental and other available results. Mg2Sn was found to be brittle in nature with a non-metallic properties as shown by the value of the Cauchy pressure of -4.03. The Phonon dispersion curve of Mg2Sn was obtained utilizing the PBE-GGA exchange-correlation potential as employed in the Vienna Ab-Initio Simulation Package (VASP) computer code. The gap separating the acoustic and the optical branch of the curve was found to be about 50cm-1 at X-point. The thermodynamic properties of the material was investigated in the temperature of 0-800K. At room temperature, the calculated value of the specific heat capacity ( ) is 71.28J/mol which is in good agreement with experimental and other results. Mg2Sn was found to a narrow gap semiconductor with an indirect bandgap of magnitude of 0.175eV.

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.

First-Principles Calculations of the Structural, Electronic, Optical and Mechanical Properties of CdS, CdSe and CdTe

2013 ◽  
Vol 665 ◽  
pp. 302-306 ◽  
Author(s):  
Sheetal Sharma ◽  
Ajay Singh Verma
Keyword(s):  
Experimental Data ◽  
Density Functional ◽  
Full Potential ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Zinc Blende ◽  
Optical And Mechanical Properties ◽  
Good Agreement

The structural, electronic, optical and elastic properties of zinc-blende compounds (CdX, X = S, Se and Te), were studied using full-potential augmented plane wave plus local orbitals method (FP-LAPW+ lo) within density functional theory, using generalized gradient approximation (GGA). Geometrical optimization of the unit cell (lattice constant, bulk modulus and its pressure derivative) is in good agreement with experimental data. Results for band structures, density of states, and elastic constants (C11, C12 and C44) are presented. We also report our results on optical properties like the complex dielectric functions and the refractive index (n) of these compounds. Our results are in reasonable agreement with the available theoretical and experimental data.

Planar Force-constant Method for Lattice Dynamics of Cubic InN

2000 ◽  
Vol 639 ◽  
Author(s):  
H. W. Leite Alves ◽  
J. L. A. Alves ◽  
L. M. R. Scolfaro ◽  
J. R. Leite
Keyword(s):  
Lattice Dynamics ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Indium Nitride ◽  
Full Potential ◽  
Phonon Modes ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
The Density Functional Theory ◽  
Good Agreement

ABSTRACTUsing the density-functional theory within the Full Potential Linear Augmented Plane-Wave (FP-LAPW) method, we have calculated, in this work, the equation of state, the effective charges and the phonon dispersion along [100] and [111] directions for the cubic Indium Nitride(c-InN), including hydrostatic strains dependence. A good agreement with the micro-Raman scattering experiment is obtained for the phonon modes at ã. Our results show that the apparent divergence between the known experimental results is a consequence of hydrostatic effects on the sample due to differences of the used Raman methods.

Structural, electronic, elastic, thermodynamic and phonon properties of LaX (X = Cd, Hg and Zn) compounds in the B2 phase

2016 ◽  
Vol 30 (24) ◽  
pp. 1650169 ◽  
Author(s):  
Osman Örnek ◽  
Nihat Arıkan
Keyword(s):  
Density Functional ◽  
Phonon Dispersion ◽  
Band Structures ◽  
Pressure Derivative ◽  
Electronic Band ◽  
Lattice Constants ◽  
Density Functional Perturbation Theory ◽  
Densities Of States ◽  
Electronic Band Structures ◽  
Phonon Properties

The ab initio computations have been performed to examine the structural, elastic, electronic and phonon properties of cubic [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] compounds in the [Formula: see text] phase. The optimized lattice constants, bulk modulus, and its pressure derivative and elastic constants are evaluated and compared with available data. Electronic band structures and total and partial densities of states (DOS) have been derived for [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] compounds. The electronic band structures show metallic character; the conductivity is mostly governed by [Formula: see text]-[Formula: see text] states for three compounds. Phonon-dispersion curves have been obtained using the first-principle linear-response approach of the density-functional perturbation theory. The specific heat capacity at a constant volume [Formula: see text] of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] compounds are calculated and discussed.

STRUCTURAL, ELECTRONIC AND PHONON PROPERTIES OF LaX COMPOUNDS (X = P, As)

2008 ◽  
Vol 22 (28) ◽  
pp. 5027-5033 ◽  
Author(s):  
GÖKAY UǦUR ◽  
ŞULE UǦUR ◽  
AYTAÇ ERKIŞI ◽  
FETHI SOYALP
Keyword(s):  
Density Functional Theory ◽  
Bulk Modulus ◽  
Density Of States ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Lattice Constants ◽  
Phonon Properties

The structural, electronic and phonon properties of the LaP and LaAs compounds in NaCl (B1) and CsCl (B2) structures are studied by means of density functional theory within the generalized gradient approximation. The calculated lattice constants, static bulk modulus and first-order pressure derivative of the bulk modulus are reported in both B1 and B2 structures and compared with previous experimental and theoretical calculations. Band structure and density of states calculations are carried out for LaP and LaAs . Then, a linear-response approach to the density functional theory is used to derive the phonon frequencies and density of states.

scholarly journals EOS parameters and elastic properties of cubic rock-salt BP

2019 ◽  
Vol 7 (1) ◽  
pp. 7
Author(s):  
Salah DAOUD
Keyword(s):  
Elastic Properties ◽  
Density Functional ◽  
Young Modulus ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Boron Phosphide ◽  
Density Functional Perturbation Theory ◽  
The Density Functional Theory ◽  
Aggregate Material ◽  
Good Agreement

The present work aims to study the equation of state (EOS) under compression up to 100 GPa, and the elastic properties of cubic rocksalt Boron phosphide (BP) material. The EOS parameters and the elastic constants of our material of interest were predicted using plane wave-pseudopotential (PW-PP) approach in the framework of the density functional theory (DFT) and the density functional perturbation theory (DFPT) with the generalized gradient approximation (GGA) for the exchange-correlation functional. The Young modulus, the Poisson's ratio, the sound velocity, the Debye temperature and the melting temperature of the aggregate material were also presented. The results obtained are in general in good agreement compared to other data of the literature.

Thermodynamic and thermoelastic properties of wurtzite-ZnS by density functional theory

2020 ◽  
Vol 105 (8) ◽  
pp. 1212-1222 ◽  
Author(s):  
Gianfranco Ulian ◽  
Daniele Moro ◽  
Giovanni Valdrè
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Mechanical Stability ◽  
Phonon Dispersion ◽  
Industrial Applications ◽  
Third Order ◽  
Functional Theory ◽  
Static Conditions ◽  
Good Agreement ◽  
Piezoelectric Constants

Abstract In the present paper, we provide a detailed theoretical investigation on fundamental thermodynamic, thermomechanical, and electronic properties of wurtzite ZnS between 0–20 GPa and 0–2000 K, obtained by ab initio density functional theory and the B3LYP functional. Several properties, such as phonon dispersion relations, elastic and piezoelectric constants, and thermodynamic and thermoelastic behaviors were calculated and reported. The analysis of the data via volume-integrated third-order Birch-Murnaghan fitting resulted in K0 = 72.17(4) GPa, K′ = 3.87(1), and V0 = 85.781(1) Å3 at T = 0 K. The Born criteria for the mechanical stability of the mineral phase showed that wurtzite is unstable above about 19 GPa in static conditions. We calculated a direct bandgap for wz-ZnS of 4.86 eV at zero compression, which became an indirect one by increasing pressure above 17 GPa. The results are in good agreement with the experimental and theoretical ones reported in the literature, and further extend the knowledge of an important zinc sulfide phase, for both geological and industrial applications.

First-principles study of structural, electronic, elastic and phonon properties of AB2O4(A = Ge,Si;B = Mg,Zn,Cd) spinel oxides

2016 ◽  
Vol 30 (03) ◽  
pp. 1650002 ◽  
Author(s):  
Abdullah Candan ◽  
Gökay Uğur
Keyword(s):  
Density Functional ◽  
Phonon Dispersion ◽  
Direct Method ◽  
Structural Parameters ◽  
Functional Theory ◽  
Phonon Dispersion Curves ◽  
Phonon Spectra ◽  
Predicted Values ◽  
First Time ◽  
Phonon Properties

The structural, electronic, elastic and phonon properties of the cubic spinels AB2O4 (A = Ge, Si; B = Mg, Zn, Cd) compounds at zero pressure are investigated via density functional theory (DFT) using the Perdew–Burke–Ernzerhof (PBE) exchange–correlation functional. It has been shown that the predicted values of the structural parameters ([Formula: see text] and [Formula: see text]), bulk modulus [Formula: see text], elastic constants [Formula: see text], shear modulus [Formula: see text] and [Formula: see text] ratio are in good agreement with the previously reported results. The phonon dispersion curves of the AB2O4 (A = Ge, Si; B = Mg, Zn, Cd) are calculated for the first time using the direct method. The estimated phonon spectra indicate that GeMg2O4, GeZn2O4, GeCd2O4, SiMg2O4 and SiZn2O4 are dynamically stable in the cubic spinel structure.

Structural, Electronic and Elastic Properties of Neptunium Bismuthide (NpBi)

2016 ◽  
Vol 1141 ◽  
pp. 180-183
Author(s):  
Chandrabhan Makode ◽  
Mahendra Aynyas ◽  
Jagdeesh Pataiya ◽  
Archana Singh ◽  
Sankar P. Sanyal
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Shear Moduli ◽  
Young’S Moduli ◽  
Theoretical Results ◽  
Good Agreement

The electronic, elastic and mechanical properties of neptunium bismuthide have been studied systematically using first principles density functional theory within generalized gradient approximation. Ground state properties such as lattice constant (a0), bulk modulus (B), its pressure derivative (B′) and elastic constants are calculated. The present results are in good agreement with the experimental and other available theoretical results. Poisson’s ratio (σ), Young’s moduli (E), shear moduli (GH) and the ratio of elastic anisotropy factor (A) are also estimated.

Synthesis of New α-Amino Phosphonates Containing 3-Amino-4(3H) Quinazolinone Moiety as Anticancer and Antimicrobial Agents: DFT, NBO, and Vibrational Studies

2018 ◽  
Vol 15 (2) ◽  
pp. 286-296 ◽  
Author(s):  
Mohamed K. Awad ◽  
Mahmoud F. Abdel-Aal ◽  
Faten M. Atlam ◽  
Hend A. Hekal
Keyword(s):  
Biological Activity ◽  
Cell Line ◽  
Quantum Chemical ◽  
Density Functional ◽  
Carcinoma Cell ◽  
Liver Carcinoma ◽  
Anticancer Activities ◽  
Functional Theory ◽  
Ft Ir ◽  
Good Agreement

Aim and Objective: Synthesis of new .-aminophosphonates containing quinazoline moiety through Kabachnik-Fields reaction in the presence of copper triflate catalyst [32], followed by studying their antimicrobial activities and in vitro anticancer activities against liver carcinoma cell line (HepG2) with the hope that new anticancer agents could be developed. Also, the quantum chemical calculations are performed using density functional theory (DFT) to study the effect of the changes of molecular and electronic structures on the biological activity of the investigated compounds. Materials and Method: The structures of the synthesized compounds are confirmed by FT-IR, 1H NMR, 13C NMR, 31P NMR and MS spectral data. The synthesized compounds show significant antimicrobial and also remarkable cytotoxicity anticancer activities against liver carcinoma cell line (HepG2). Density functional theory (DFT) was performed to study the effect of the molecular and electronic structure changes on the biological activity. Results: It was found that the electronic structure of the substituents affects on the reaction yield. The electron withdrawing substituent, NO2 group 3b, on the aromatic aldehydes gave a good yield more than the electron donating substituent, OH group 3c. The electron deficient on the carbon atom of the aldehydic group may increase the interaction of the Lewis acid (Cu(OTf)2) and the Lewis base (imine nitrogen), and accordingly, facilitate the formation of imine easily, which is attacked by the nucleophilic phosphite species to give the α- aminophosphonates. Conclusion: The newly synthesized compounds exhibit a remarkable inhibition of the growth of Grampositive, Gram-negative bacteria and fungi at low concentrations. The cytotoxicity of the synthesized compounds showed a significant cytotoxicity against the liver cancer cell line (HepG 2). Also, it was shown from the quantum chemical calculations that the electron-withdrawing substituent increases the biological activity of the α-aminophosphonates more than the electron donating group which was in a good agreement with the experimental results. Also, a good agreement between the experimental FT-IR and the calculated one was found.

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