scholarly journals Mechanical Response of PbSSe, PbSTe Ternary and PbSnSTe Quaternary Alloys at High Pressure

2020 ◽  
Vol 8 (2) ◽  
pp. 29-33
Author(s):  
Mazin Sh. Othman
Keyword(s):  
High Pressure ◽  
Density Functional ◽  
Mechanical Response ◽  
Ternary Alloys ◽  
Published Data ◽  
Quaternary Alloys ◽  
Linear Elasticity Theory ◽  
Functional Theory ◽  
Lattice Matching ◽  
The Density Functional Theory

Property of the semiconductors under high pressure is investigated by the density functional theory and paralleled to the foretelling of the linear elasticity theory. In addition, ternary alloys of  PbSxSe1-x and  PbSxTe1-x lattice matching PbS substrate for x = 0.5 compositions are studied. Furthermore, quaternary alloys PbxSn1-xSyTe1-y lattice matching PbS substrate for x  and y = 0.5 compositions are studied. The six independent elastic parameters (Cij) are also calculated. Meanwhile, the results data are analyzed in high pressure. The mechanical response of all alloys to pressures 0, 50, and 100 kbar increases progress to decrease in (Cij) in separate rates. The rapprochement between the calculated results and the available published data for these alloys demonstrate that they had worthy accordance at zero pressure and the results at high pressure may be required as an acceptable reference.

scholarly journals DFT Calculations of the Structural, Mechanical, and Electronic Properties of TiV Alloy Under High Pressure

Symmetry ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 972 ◽  
Author(s):  
Fang Yu ◽  
Yu Liu
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Electronic Properties ◽  
Structural Phase Transition ◽  
Density Functional ◽  
Structural Phase ◽  
Applied Pressure ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Dimensionless Ratio

A calculation program based on the density functional theory (DFT) is applied to study the structural, mechanical, and electronic properties of TiV alloys with symmetric structure under high pressure. We calculate the dimensionless ratio, elastic constants, shear modulus, Young’s modulus, bulk modulus, ductile-brittle transition, material anisotropy, and Poisson’s ratio as functions of applied pressure. Results suggest that the critical pressure of structural phase transition is 42.05 GPa for the TiV alloy, and structural phase transition occurs when the applied pressure exceeds 42.05 GPa. High pressure can improve resistance to volume change, as well as the ductility and atomic bonding, but the strongest resistances to elastic and shear deformation occur at P = 5   GPa for TiV alloy. Furthermore, the results of the density of states (DOS) indicate that the TiV alloy presents metallicity. High pressure disrupts the structural stability of the TiV alloy with symmetry, thereby inducing structural phase transition.

Structural, elastic and vibrational properties of nanocrystalline lutetium gallium garnet under high pressure

2015 ◽  
Vol 17 (14) ◽  
pp. 9454-9464 ◽  
Author(s):  
V. Monteseguro ◽  
P. Rodríguez-Hernández ◽  
H. M. Ortiz ◽  
V. Venkatramu ◽  
F. J. Manjón ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Ab Initio ◽  
Density Functional ◽  
Vibrational Properties ◽  
Functional Theory ◽  
The Density Functional Theory

An ab initio study of the structural, elastic and vibrational properties of the lutetium gallium garnet (Lu3Ga5O12) under pressure has been performed in the framework of the density functional theory, up to 95 GPa.

First-principles study on structural, elastic and thermal properties of γ-TiAl and α2-Ti3Al phases in TiAl-based alloy under high pressure

2017 ◽  
Vol 31 (11) ◽  
pp. 1750079 ◽  
Author(s):  
Chaoyan Zhang ◽  
Hua Hou ◽  
Yuhong Zhao ◽  
Xiaomin Yang ◽  
Yaqiong Guo
Keyword(s):  
High Pressure ◽  
Thermal Properties ◽  
Density Functional ◽  
Theoretical Data ◽  
Debye Model ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Two Phases ◽  
Calculated Equilibrium ◽  
Good Agreement

The structural, elastic and thermal properties of [Formula: see text]-TiAl and [Formula: see text]-Ti3Al phases in the TiAl-based alloy under pressure were reported using CASTEP program based on the density functional theory. The calculated equilibrium parameters and elastic constants are in good agreement with experimental and the available theoretical data. The results indicate that under the same pressure, the [Formula: see text] phase in the direction along [Formula: see text]-axis is easier to be compressed than the [Formula: see text] phase, while the compression along [Formula: see text]-axis of [Formula: see text] phase is larger than that of [Formula: see text] phase; when the pressure is below 20 GPa, both the two phases are elastically stable, but the [Formula: see text] phase have higher shear modulus and Young’s modulus, and the [Formula: see text] phase has better ductility and plasticity. Debye temperature, bulk modulus, thermal expansion coefficient and heat capacity of the [Formula: see text] phase and [Formula: see text] phase under high pressure and high temperature were also successfully calculated and compared using the quasi-harmonic Debye model in the present work.

scholarly journals Numerical Investigation of the Stability and Spintronic Properties of Selected Quaternary Alloys

2021 ◽  
Vol 3 (4) ◽  
pp. 6-12
Author(s):  
Adewumi I. Popoola ◽  
S. Babatunde Akinpelu
Keyword(s):  
Data Storage ◽  
Density Functional ◽  
First Principles Calculation ◽  
Electronic Charge ◽  
Quaternary Alloys ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Ferromagnetic Character ◽  
The Stability ◽  
Full Heusler

The use of electronic charge and spins (spintronics) has been proposed for much better data storage. This class of material is believed to have excellent capability for data integrity, low dynamic power consumption and high-density storage that showcases excellent protection against data loss. The spintronic and related properties have been investigated on four newly proposed quaternary alloys (NbRhGeCo, NbRhGeCr, NbRhGeFe and NbRhGeNi) through the first-principles calculation method of the Density Functional Theory (DFT). Specifically, the phonon frequencies, elastic stabilities, and the electronic structure were systematically studied in the full Heusler structure. The results predict that NbRhGeFe and NbRhGeCr are elastically and structurally stable. Both NbRhGeFe and NbRhGeCo are half-metals with ferromagnetic character, but NbRhGeCo is unfortunately elastically unstable. NbRhGeCr and NbRhGeNi are non-magnetic metallic alloys in their spin channels.  All the results predict NbRhGeFe to be the only suitable among all the four alloys for spintronic application.

scholarly journals Crystal structure of rare earth and group III nitride alloys by ab initio calculations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Maciej J. Winiarski ◽  
Dorota A. Kowalska
Keyword(s):  
Rare Earth ◽  
Density Functional ◽  
Metastable Phase ◽  
Rare Earth Ions ◽  
Ternary Alloys ◽  
Wurtzite Phase ◽  
Functional Theory ◽  
Group Iii ◽  
The Density Functional Theory ◽  
Group Iii Nitride

Abstract The ground state phases of ternary alloys of rare earth and group III nitride semiconductors have been investigated within the density functional theory. The most energetically favorable crystal phases among possible cubic and hexagonal structures, i.e., the rock salt, zinc blende, wurtzite, and hexagonal BN, were determined. The type of a unit cell and the lattice parameters of the materials are presented as a function of their composition. Furthermore, effects of strain on ground states of group III and rare earth nitride materials are discussed. The findings presented in this work discloses the wurtzite type materials as being stable with relatively low contents of rare earth elements. It is expected that the wurtzite phase will be very persistent only in the La-based systems. Nevertheless, the two-dimensional hexagonal atomic layers are revealed as being a metastable phase for all alloys studied. This finding supports the conclusion of previous experimental reports for Sc-doped GaN systems that the presence of rare earth ions in group III nitride materials leads to flattening of the wurtzite type layers.

Pressure effect on the mechanical and electronic properties of orthorhombic-C20

2018 ◽  
Vol 32 (31) ◽  
pp. 1850380 ◽  
Author(s):  
Jian-Li Ma ◽  
Zhi-Fen Fu ◽  
Qun Wei ◽  
Peng Liu ◽  
Jian-Ping Zhou
Keyword(s):  
High Pressure ◽  
Electronic Properties ◽  
Debye Temperature ◽  
Density Functional ◽  
Superhard Material ◽  
Elastic Anisotropy ◽  
Systematic Investigation ◽  
Functional Theory ◽  
Temperature Changes ◽  
The Density Functional Theory

A systematic investigation of structural, mechanical, elastic anisotropy and electronic properties of a recently reported novel superhard material orthorhombic [Formula: see text] ([Formula: see text]-[Formula: see text]) under pressure is performed utilizing the density functional theory in this work. The crystal structure parameters are obtained at zero as well as at high pressure. Pressure induced elastic constants [Formula: see text], polycrystalline aggregate elastic modulus [Formula: see text], [Formula: see text] ratio, and Debye temperature changes for [Formula: see text]-[Formula: see text] have been determined. The crystal elastic anisotropies of the ultra-incompressible [Formula: see text]-[Formula: see text] are investigated in the pressure range of 0–100 GPa. The Lyakhov–Oganov model is applied to predict the hardness as functions of pressure. The calculated results reveal that [Formula: see text]-[Formula: see text] possesses high elastic anisotropy under zero pressure and high pressure, and the hardness of [Formula: see text]-[Formula: see text] decreases with pressure, while the Debye temperature behaves with the opposite trend. The results of electronic structure indicate that [Formula: see text]-[Formula: see text] exhibits insulator characteristics, and the band gap increases with pressure. This work is expected to provide a useful guide for the future synthesis and application of [Formula: see text]-[Formula: see text].

scholarly journals Магнитострикция в сплавах Fe-=SUB=-75-=/SUB=-Ga-=SUB=-25-x-=/SUB=-Z-=SUB=-x-=/SUB=- (Z=Al, Ge, Si): расчет методом магнитного вращающего момента

2021 ◽  
Vol 63 (11) ◽  
pp. 1745
Author(s):  
М.В. Матюнина ◽  
М.А. Загребин ◽  
В.В. Соколовский ◽  
В.Д. Бучельников
Keyword(s):  
Elastic Modulus ◽  
Density Functional ◽  
Ternary Alloys ◽  
Ab Initio Study ◽  
Magnetic Torque ◽  
Functional Theory ◽  
Cubic Crystal ◽  
Lattice Constants ◽  
Magnetoelastic Properties ◽  
The Density Functional Theory

This work presents an ab initio study of the effect of a small addition of the third element of III and IV groups on the elastic and magnetoelastic properties of Fe75Ga25 alloy. The dependencies of the tetragonal elastic modulus C', magnetoelastic constant –b1, and the tetragonal magnetostrictive constant λ001 on the concentration of the Z-element in the cubic crystal structures A2 and D03 were obtained with the help of the density functional theory and the magnetic torque method in Fe75Ga25-xZx (Z = Al, Ge, Si) alloys (0≤x≤6 at.%). It is shown that the addition of Al and Si atoms leads to an increase in the tetragonal elastic modulus compared to the Fe75Ga25 binary alloy. A correlation was established in the dependence equilibrium lattice constants a0(x) and λ001(x) in the studied ternary alloys for the A2 structure.

First-Principles Study of the Effect of Cr Content on Interstitial Oxygen Solution Behavior in Nb-Cr Alloys

2018 ◽  
Vol 913 ◽  
pp. 582-588
Author(s):  
Jin Wang ◽  
Li Ming Yu ◽  
Yong Chang Liu ◽  
Chen Xi Liu ◽  
Hui Jun Li ◽  
...  
Keyword(s):  
Density Functional ◽  
Ternary Alloys ◽  
Interstitial Oxygen ◽  
Solution Behavior ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Two Factors ◽  
Oxygen Solution ◽  
Cr Concentration ◽  
Interstitial Elements

The solution behavior of oxygen atom in Nb-Cr alloys was investigated by employing the density-functional theory. The solution behavior mainly depends on two factors, namely, the elastic and chemical interactions. We proposed a method to separate these two parts and applied it in Nb-Cr-O system to investigate the effect of alloying Cr concentration on the solution behavior of interstitial oxygen atoms. This method can be useful for understanding and predicting the solution behavior in ternary alloys which contain interstitial elements.

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