Computational Study of Ru2TiZ (Z = Si, Ge, Sn) for Structural, Mechanical and Vibrational Properties

AbstractThe structural, mechanical and vibrational properties of Ru2TiZ (Z = Si, Ge, Sn) Full Heusler Alloys (FHAs) are computed using PBE-GGA as an exchange-correlation functional in Kohn–Sham equations. The calculated lattice constants of these alloys in L21 phase deviate from experimental values upto 0.85 % which shows a good agreement between the model and the experiments. These lattice constants are then used to compute the second order elastic constants C11, C12 and C44 with Wien2k-code. Elastic moduli and mechanical parameters are also calculated by these three independent elastic constants. Mechanical parameters Pugh’s and Poisson’s ratio indicate non-brittle nature of these alloys. Furthermore, the Debye temperature where the collective vibrations shift to an independent thermal vibration, longitudinal and transverse sound velocities, melting temperatures, and thermal conductivities are also obtained to investigate the phonon modes of oscillation. These phonon modes confirm the stability of these alloys as there exists no imaginary phonon frequency in the phonon-dispersion curves.

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The Pressure Dependence of Structural, Electronic, Mechanical, Vibrational, and Thermodynamic Properties of Palladium-Based Heusler Alloys

Zeitschrift für Naturforschung A ◽

10.1515/zna-2017-0130 ◽

2017 ◽

Vol 72 (9) ◽

pp. 843-853 ◽

Cited By ~ 1

Author(s):

Cansu Çoban

Keyword(s):

Thermodynamic Properties ◽

Elastic Constants ◽

Phonon Dispersion ◽

Electronic Band Structure ◽

Heusler Alloys ◽

Dispersion Curves ◽

Pressure Derivative ◽

Electronic Band ◽

Phonon Dispersion Curves ◽

The Stability

AbstractThe pressure dependent behaviour of the structural, electronic, mechanical, vibrational, and thermodynamic properties of Pd2TiX (X=Ga, In) Heusler alloys was investigated by ab initio calculations. The lattice constant, the bulk modulus and its first pressure derivative, the electronic band structure and the density of states (DOS), mechanical properties such as elastic constants, anisotropy factor, Young’s modulus, etc., the phonon dispersion curves and phonon DOS, entropy, heat capacity, and free energy were obtained under pressure. It was determined that the calculated lattice parameters are in good agreement with the literature, the elastic constants obey the stability criterion, and the phonon dispersion curves have no negative frequency which shows that the compounds are stable. The band structures at 0, 50, and 70 GPa showed valence instability at the L point which explains the superconductivity in Pd2TiX (X=Ga, In).

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Study of thermo-elastic and lattice dynamics properties of half-Heusler compounds XMgAl (X = Li, Na) by computational investigations

Modern Physics Letters B ◽

10.1142/s0217984919500933 ◽

2019 ◽

Vol 33 (08) ◽

pp. 1950093 ◽

Cited By ~ 1

Author(s):

A. Afaq ◽

Abu Bakar ◽

M. Rizwan ◽

M. Aftab Fareed ◽

H. Bushra Munir ◽

...

Keyword(s):

Debye Temperature ◽

Elastic Constants ◽

Density Functional ◽

Phonon Dispersion ◽

Dynamic Properties ◽

Mechanical Parameters ◽

Heusler Compounds ◽

Generalized Gradient ◽

Text Type ◽

Quantum Espresso

In this study, thermo-elastic and lattice dynamic properties of XMgAl (X = Li, Na) half-Heusler compounds are investigated using density functional theory implemented in WIEN2k and Quantum ESPRESSO codes. Generalized gradient approximation (GGA) as an exchange correlation function has been used in Kohn–Sham equations. Firstly, the structure of these Heusler compounds is optimized and then these optimized parameters are used to find three elastic constants [Formula: see text], [Formula: see text] and [Formula: see text] for [Formula: see text] type structures. Three elastic constants are then used to determine different elastic moduli like bulk modulus, shear modulus, Young’s modulus and other mechanical parameters like Pugh’s ratio, Poisson’s ratio, anisotropic ratio, sound velocities, Debye temperature and melting temperature. On behalf of these mechanical parameters, the brittle/ductile nature and isotropic/anisotropic behavior of the materials has been studied. Different regions of vibrational modes in the materials are also discussed on behalf of Debye temperature calculations. The vibrational properties of the half-Heusler compounds are computed using Martins–Troullier pseudo potentials implemented in Quantum ESPRESSO. The phonon dispersion curves and phonon density of states in first Brillion zone are obtained and discussed. Reststrahlen band of LiMgAl is found greater than NaMgAl.

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A Theoretical Analysis of Physical Properties and Half-Metallic Stability under Pressure Effect of the ScNiCrZ (Z=Ga, Al, In) Heusler Alloys

SPIN ◽

10.1142/s2010324721500077 ◽

2021 ◽

pp. 2150007

Author(s):

I. E. Rabah ◽

H. Rached ◽

M. Rabah ◽

D. Rached ◽

N. Benkhettou

Keyword(s):

Heusler Alloys ◽

Ferromagnetic Behavior ◽

Full Potential ◽

Half Metallicity ◽

Half Metallic ◽

Lattice Constants ◽

Wide Range ◽

Quaternary Heusler Alloys ◽

Lmto Method ◽

The Stability

The aim purpose of this study is to investigate the structural, elastic, magnetic, electronic properties and half-metallic stability under pressure of ScNiCrZ ([Formula: see text], Ga and In) quaternary Heusler alloys using full-potential linear muffin-tin orbital (FP-LMTO) method within the gradient generalized approximation (GGA) for exchange, and correlation potential. In order to evaluate the stability of our compounds, the formation energy, and elastic constants have been evaluated. The results showed that our compounds have ferromagnetic ground states and are energetically more stable in type-[Formula: see text] configuration. True half-metallic ferromagnetic behavior with 100% spin polarization at Fermi level [Formula: see text] with high Curie temperature [Formula: see text], and very interesting bandgap in the minority spin are obtained for the three alloys. The calculated total magnetic moment [Formula: see text] for all three alloys is consistent with Slater[Formula: see text]Pauling rule. The half-metallicity is maintained over a wide range of lattice constants making these alloys promising for spintronic, and magneto-electronics applications.

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Structural, elasto-mechanical and phonon-related properties of MnCrP: A DFT Study

International Journal of Modern Physics B ◽

10.1142/s0217979220502008 ◽

2020 ◽

Vol 34 (21) ◽

pp. 2050200

Author(s):

A. Afaq ◽

Abu Bakar ◽

Muhammad Shoaib ◽

Rashid Ahmed ◽

Anila Asif

Keyword(s):

Mechanical Stability ◽

Phonon Dispersion ◽

Structural Parameters ◽

Far Infrared ◽

Phonon Modes ◽

Phonon Dispersion Curves ◽

Anisotropic Factor ◽

Cauchy Pressure ◽

The Stability ◽

Thermal Vibrations

The Half Heusler alloy (HHA) MnCrP has been studied theoretically for structural, elasto-mechanical and phonon properties. The structure is optimized and the calculated structural parameters are close to the literature. This optimized data is used to estimate three independent second-order cubic elastic constants [Formula: see text], [Formula: see text] and [Formula: see text]. The mechanical stability criteria are explored by these constants and further used to estimate the elastic moduli; Young’s, bulk and shear modulus. The mechanical parameters like Poisson’s ratio, Pugh’s ratio, anisotropic factor, Cauchy pressure, shear constant, Lame’s constants, Kleinman parameter are also calculated and discussed. Discussions reveal the ductile nature, ionic behavior, anisotropic nature and mechanical stability of MnCrP. The metallic nature, compressibility, stiffness and interatomic forces of material are also described. Furthermore, the Debye temperature, where the collective vibrations shifts to an independent thermal vibrations, is also calculated. Longitudinal and transverse sound velocities are also obtained to investigate the phonon modes of oscillation. These phonon modes confirm the stability of the alloy as no negative phonon frequencies in the phonon-dispersion curves. These curves are used to estimate the reststrahlen band where light reflects 100% and the suitability of material is checked for Far Infrared (FIR), photographic, optoelectronic devices and sensors.

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Theoretical study of phonon dispersion, elastic, mechanical and thermodynamic properties of barium chalcogenides

International Journal of Modern Physics B ◽

10.1142/s0217979218500923 ◽

2018 ◽

Vol 32 (08) ◽

pp. 1850092 ◽

Cited By ~ 2

Author(s):

A. A. Musari ◽

S. A. Orukombo

Keyword(s):

Thermodynamic Properties ◽

Elastic Constants ◽

Density Functional ◽

Phonon Dispersion ◽

Potential Method ◽

Generalized Gradient ◽

Functional Theory ◽

Lattice Constants ◽

Linear Fit ◽

Specific Heat Capacities

Barium chalcogenides are known for their high-technological importance and great scientific interest. Detailed studies of their elastic, mechanical, dynamical and thermodynamic properties were carried out using density functional theory and plane-wave pseudo potential method within the generalized gradient approximation. The optimized lattice constants were in good agreement when compared with experimental data. The independent elastic constants, calculated from a linear fit of the computed stress–strain function, were used to determine the Young’s modulus (E), bulk modulus (B), shear modulus (G), Poisson’s ratio ([Formula: see text]) and Zener’s anisotropy factor (A). Also, the Debye temperature and sound velocities for barium chalcogenides were estimated from the three independent elastic constants. The calculations of phonon dispersion showed that there are no negative frequencies throughout the Brillouin zone. Hence barium chalcogenides have dynamically stable NaCl-type crystal structure. Finally, their thermodynamic properties were calculated in the temperature range of 0–1000 K and their constant-volume specific heat capacities at room-temperature were reported.

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First Principle Study of Ti50Al50 Alloys

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.770.224 ◽

2018 ◽

Vol 770 ◽

pp. 224-229

Author(s):

Rosinah Modiba ◽

Hasani Chauke ◽

Phuti Ngoepe

Keyword(s):

Experimental Data ◽

High Temperatures ◽

Elastic Constants ◽

Martensitic Phase ◽

First Principle ◽

Lattice Constants ◽

B2 Phase ◽

Experimental Values ◽

Good Agreement

The study on the Ti-based materials and its application has been the interest of many research industries. These alloys are known to have an ordered B2 phase at high temperatures and transform to a stable low B19 martensitic phase. First principle approach has been used to study L10, B32, B2 and B19 Ti50Al50alloys and the results compared well with the available experimental data. The equilibrium lattice constants are in good agreement with the experimental values (within 3% agreement). Furthermore, the elastic constants of these alloys are calculated, and revealed stability for L10and B19 structures, while B2 and B32 gave C′<0 (condition of instability).

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Theoretical Prediction on Mechanical, Dynamic, and Thermodynamic Properties of C11b-Structured WSi2 under Pressure

Zeitschrift für Naturforschung A ◽

10.1515/zna-2018-0308 ◽

2018 ◽

Vol 74 (1) ◽

pp. 83-89 ◽

Cited By ~ 2

Author(s):

ShunRu Zhang ◽

DuoPeng Zeng ◽

HaiJun Hou ◽

You Yu

Keyword(s):

Thermodynamic Properties ◽

Elastic Constants ◽

Phonon Dispersion ◽

Structural Parameters ◽

Harmonic Approximation ◽

Three Dimensional ◽

Mechanical Anisotropy ◽

Phonon Dispersion Curves ◽

Lattice Constants ◽

Experimental Findings

AbstractThe structural parameters, mechanical, dynamic, and thermodynamic properties of WSi2 with the C11b structure under pressure were systematically explored by using first-principles calculations. The results shown that calculated lattice constants and elastic constants of WSi2 were consistent with previous experimental findings and theoretical values. Our obtained elastic constants revealed that WSi2 was mechanically stable from 0 to 100 GPa. The values of anisotropic indexes, three-dimensional surface constructions, and two-dimensional projections under pressure indicated that WSi2 showed mechanical anisotropy. Additionally, the phonon density of state and phonon dispersion curves under pressure were obtained, and all vibration modes were analyzed. Finally, thermodynamic properties were also predicted based on quasi-harmonic approximation.

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First Principles Study of Electronic and Elastic Properties of AlY

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1047.45 ◽

2014 ◽

Vol 1047 ◽

pp. 45-50

Author(s):

Mani Shugani ◽

Mahendra Aynyas ◽

S.P. Sanyal

Keyword(s):

Elastic Properties ◽

Elastic Constants ◽

Ground State ◽

Full Potential ◽

Augmented Plane Wave ◽

Plane Wave Method ◽

Lattice Constants ◽

Ground State Properties ◽

Experimental Values ◽

Good Agreement

We have used full potential linear augmented plane wave method within thegeneralized gradient approximation to investigate the structural, electronic and elastic properties of the AlY. The ground state properties are determined for the AlY. The calculated ground state properties such as lattice constants, bulk modulus and elastic constants agree well with the experimental values. From band structure curves it is found that AlY is metallic in nature. The elastic constants are in good agreement with previous theoretical and experimental results.

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Effects of Ga content on the stability of Fe-X (X = 6.25, 12.5, 18.75, 25 at.% Ga) alloys from first-principles calculations

Modern Physics Letters B ◽

10.1142/s0217984917500981 ◽

2017 ◽

Vol 31 (09) ◽

pp. 1750098 ◽

Cited By ~ 1

Author(s):

Xiang-Hong Yan ◽

Ya-Ning Lin

Keyword(s):

Elastic Constant ◽

Elastic Constants ◽

First Principles ◽

Cohesive Energy ◽

Density Functional ◽

Phonon Dispersion ◽

First Principles Calculations ◽

Good Accordance ◽

The Stability ◽

Ga Content

First-principles calculations based on density functional theory (DFT) were employed to investigate the influence of Ga concentration on the stability of binary Fe–Ga alloy. The contents of Ga element are 6.25, 12.5, 18.75 and 25 at.% for Fe[Formula: see text]Ga, Fe[Formula: see text]Ga, Fe[Formula: see text]Ga[Formula: see text] and Fe[Formula: see text]Ga alloys, respectively. Cohesive energy, elastic properties, electronic structures and phonon properties of optimized Fe–Ga models were calculated. Our results of calculated elastic constants and elastic moduli are in good accordance with the determined available literature. Our study shows that with increasing Ga content, the absolute value of cohesive energy of Fe–Ga alloy is decreasing. From the calculations of elastic constants, we found that the value of [Formula: see text] decreases with the increasing Ga content, which indicates that the stability of Fe–Ga along the [001] direction is decreasing with the increasing Ga content. The calculated bulk moduli of Fe–Ga alloys increase with increasing Ga content because of the increase of the average bonding number evaluated by our calculations of densities of states. Conversely, the shear moduli decrease with increasing Ga content, which indicates that the stability of Fe–Ga is decreasing with the increasing Ga content. Tetragonal shear elastic constant [Formula: see text] almost decreases linearly with increasing Ga content, which follows the same decreasing trend as the cohesive energy and the shear modulus. It is worth noting that with the increasing Ga content, the pseudogap between two major peaks in the minority-spin state became softer. The softness brings the Fermi level into a high state, which lowers the stability of the Fe–Ga alloy. According to the phonon calculations, the acoustic mode of Fe-25 at.% Ga appeared to be softening along the [001] direction, which is in good accordance with the direction predicted by the calculations of elastic constant. But this softening trend cannot be observed in the phonon dispersion spectrum of Fe-6.25 at.% Ga, which proved that Fe-6.25 at.% Ga is more stable than the Fe-25 at.% Ga alloy.

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Derivation of Many-Body Potentials for Examining Defect Behavior in Bcc Niobium

MRS Proceedings ◽

10.1557/proc-141-285 ◽

1988 ◽

Vol 141 ◽

Cited By ~ 1

Author(s):

James M. Eridon ◽

Satish Rao

Keyword(s):

Elastic Constants ◽

Defect Formation ◽

Phonon Dispersion ◽

Pair Potential ◽

Difficult Problem ◽

Many Body ◽

Lattice Constants ◽

Embedded Atom ◽

Straightforward Method ◽

Formation Energies

AbstractMany-body potentials, in either the Embedded Atom or Finnis-Sinclair form, have gained wide popularity recently. The major difficulty in implementing the method concerns the derivation of suitable forms for the pair potential, electron density, and embedding, function which reproduce a range of empirically observable parameters such as elastic constants, defect formation energies, and defect Green's functions. This is a particularly difficult problem for niobium, which shows a variety of anomalous features in its phonon dispersion. Embedding functions which match only elastic constants may do a poor job of reproducing short wavelength behavior, and hence provide poor defect modeling. A straightforward method of deriving embedding functions for homonuclear BCC andFCC metals will be presented which provides excellent agreement with experimental phonon dispersion curves and elastic constants, as well as Griineisen coefficients, vacancy formation energies, lattice constants and heats of sublimation. The results of the application of a set of many-body potentials derived in this fashion to nitrogen irradiated niobium will be presented.

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