First-principles study of the structure, elastic constants, electronic and thermodynamic properties of C15 laves phase ZrMo2

2020 ◽  
Vol 34 (18) ◽  
pp. 2050170
Author(s):  
Xianbo Liu ◽  
Jun Zhu
Keyword(s):  
Thermodynamic Properties ◽  
Elastic Constants ◽  
Density Functional ◽  
Debye Model ◽  
State Density ◽  
Electronic Density ◽  
Plane Wave Method ◽  
Electron State Density ◽  
Phonon Spectra ◽  
Theoretical Simulations

The structure, elastic constants and electron state density of ZrMo2 in [Formula: see text]15 phase are investigated by pseudopotential plane-wave method based on density functional theory (DFT). The thermodynamic properties are studied with the quasi-harmonic Debye model. The calculated results are in good agreement with the previous experimental results and theoretical simulations. The calculated phonon spectra and elastic constants show that [Formula: see text]15 phase of ZrMo2 is mechanically stable. Through the analysis of [Formula: see text]/[Formula: see text] value and Poisson’s ratio, [Formula: see text]15 phase of ZrMo2 shows ductility at 0–150 GPa, and it increases with the increment of pressure. We further explore the mechanism of the metallic properties by analyzing the electronic density of states. In addition, Debye temperature, thermal expansion coefficient and heat capacity as a function of pressure and temperature is discussed, respectively.

First-principles study of the phonon, mechanical and thermodynamic properties of B2-phase AlY under high pressures

2017 ◽  
Vol 31 (32) ◽  
pp. 1750254
Author(s):  
Leini Wang ◽  
Zhang Jian ◽  
Wei Ning
Keyword(s):  
High Pressure ◽  
Thermodynamic Properties ◽  
Elastic Constants ◽  
First Principles ◽  
Density Functional ◽  
High Pressures ◽  
Mechanical Stability ◽  
Debye Model ◽  
Functional Theory ◽  
B2 Phase

We have investigated the phonon, mechanical and thermodynamic properties of B2-phase AlY under high pressure by performing density functional theory (DFT). The result of phonon band structure shows B2-phase AlY exhibits dynamical stability. Then, the elastic properties of AlY under high pressure have been discussed. The elastic constants of AlY increase monotonically with the increase of the pressure and all the elastic constants meet the mechanical stability standard under high pressure. By analyzing the Poisson’s ratio [Formula: see text] and the value of B/G of AlY, we first predicted that AlY undergoes transformation from brittleness to ductility at 30 GPa and high pressure can improve the ductility. To obtain the thermodynamic properties of B2-phase AlY, the quasi-harmonic Debye model has been employed. Debye temperature [Formula: see text], thermal expansion coefficient [Formula: see text], heat capacity C[Formula: see text] and Grüneisen parameter [Formula: see text] of B2-phase AlY are systematically explored at pressure of 0–75 GPa and temperature of 0–700 K.

The structure, elastic and thermodynamic properties of Ti2GaC from first-principles calculation

2019 ◽  
Vol 33 (06) ◽  
pp. 1950030 ◽  
Author(s):  
Xiao-Xia Pu ◽  
Xiao-Jiang Long ◽  
Lin Zhang ◽  
Jun Zhu
Keyword(s):  
Thermodynamic Properties ◽  
Elastic Constant ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Theoretical Data ◽  
Debye Model ◽  
First Principles Calculation

In this work, the structure, elastic and thermodynamic properties of Ti2GaC at high pressure (P) and high-temperature (T) are studied based on the density functional first-principles. The lattice parameters and elastic constants are well consistent with some theoretical data and experimental results. The elastic constant of Ti2GaC increase monotonously with the increase of pressure (P), which demonstrates the mechanical stability of Ti2GaC at the pressure (P) from 0 to 200 GPa. Mechanical properties including Poisson’s ratio ([Formula: see text]), Young’s modulus (E), shear modulus (G) and bulk modulus (B), which are obtained from elastic constants C[Formula: see text]. The ratio B/G value shows that Ti2GaC is a brittle material, but its enhancing ductility significantly with the elevate of pressure (P). The Grüneisen parameters ([Formula: see text]), thermal expansion coefficient ([Formula: see text]), heat capacity (C[Formula: see text]), elastic constant (C[Formula: see text]), bulk modulus (B), energy (E) and volume (V) with the change of temperature (T) or pressure (P) are calculated within the quasi-harmonic Debye model for pressure (P) and temperatures (T) range in 1600 K and 100 GPa. Besides, densities of states and energy band are also obtained and analyzed in comparison with available theoretical data.

FIRST-PRINCIPLE INVESTIGATION OF ELECTRIC STRUCTURES AND THERMODYNAMIC PROPERTIES FOR ZIRCONIUM NITRIDE UNDER HIGH PRESSURE

2013 ◽  
Vol 27 (14) ◽  
pp. 1350040 ◽  
Author(s):  
CUI-MING TANG ◽  
XIAO-XU CHEN ◽  
JUN WANG ◽  
YAN-FEI HU ◽  
HONG-YAN WANG
Keyword(s):  
Phase Transition ◽  
Thermodynamic Properties ◽  
Elastic Constants ◽  
Density Functional ◽  
Structural Phase ◽  
Debye Model ◽  
Lattice Parameter ◽  
Zirconium Nitride ◽  
Generalized Gradient ◽  
Strain Equation

In the frame of density functional theory, first-principles calculations have been carried out to investigate the structures, elastic constants, structural phase transition between B1 and B2 phases and thermodynamic properties of the zirconium nitride ( ZrN ) by means of the generalized gradient approximation. The equilibrium lattice parameter we obtained for ZrN in B1 phase is closer to the experiment results than previous theoretical results. In addition, the calculations of the elastic constants show that ZrN is a brittle material. What is more, based on third-order natural strain equation of state, the phase transition pressure 338 GPa for ZrN is predicted for B1–B2 transition. According to the quasi-harmonic Debye model, the thermodynamic parameters of ZrN have been investigated systematically.

Phonon, elastic and thermodynamic properties of L12 phase Rh3Zr under pressure from first-principles

2017 ◽  
Vol 28 (07) ◽  
pp. 1750098
Author(s):  
Leini Wang ◽  
Zhang Jian ◽  
Wei Ning
Keyword(s):  
High Pressure ◽  
Thermodynamic Properties ◽  
Elastic Constants ◽  
Density Functional ◽  
Pressure Range ◽  
Harmonic Approximation ◽  
Debye Model ◽  
Theory Approach ◽  
Wide Pressure Range ◽  
The Stability

The phonon, elastic and thermodynamic properties of L12 phase Rh3Zr have been investigated by density functional theory approach combining with quasi-harmonic approximation model. The relaxed lattice parameters of L12 phase Rh3Zr at zero pressure are in good agreement with the experiment. To judge the stability of L12 phase Rh3Zr under high pressure, the phonon band structure has been studied. The results show that L12 phase Rh3Zr possesses dynamical stability in the pressure range from 0[Formula: see text]GPa to 80[Formula: see text]GPa due to the absence of imaginary frequencies. The pressure dependences of elastic constants [Formula: see text] have been analyzed. All the elastic constants of Rh3Zr in a wide pressure range (0–80[Formula: see text]GPa) meet general mechanical conditions, suggesting that L12 phase Rh3Zr is mechanically stable under pressure up to 80[Formula: see text]GPa. L12 phase Rh3Zr exhibits ductility under high pressure and the pressure can improve the ductility from the results of the value of [Formula: see text] and Poisson’s ratio [Formula: see text]. Hence, it is obvious that the mechanical properties of Rh3Zr can be improved under high pressure. Moreover, we have obtained the thermodynamic properties using the quasi-harmonic Debye model. We note that the effect of the temperature on the Debye temperature [Formula: see text] is smaller than that of the pressure. We believe that our result will be a good guidance to future works and applications.

Theoretical Prediction on the Structural, Electronic, Mechanical, and Thermodynamic Properties of TaSi2 with a C40 Structure Under Pressure

2019 ◽  
Vol 74 (4) ◽  
pp. 353-361 ◽  
Author(s):  
HuaJun Zhu ◽  
Tao Yang ◽  
Yang Zhou ◽  
SuDong Hua ◽  
JinWen Yang
Keyword(s):  
Thermodynamic Properties ◽  
Elastic Constants ◽  
Electronic Structures ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Structural Parameters ◽  
Applied Pressure ◽  
Three Dimensional ◽  
Debye Model ◽  
Experimental Findings

AbstractThe structural parameters, electronic structures, and mechanical and thermodynamic properties of TaSi2 under different pressures have been completely explored by a combination of density functional theory and quasi-harmonic Debye model. Results show that our computed structural parameters and elastic constants are in consistency with available experimental findings and previous theoretical calculations. The electronic structures of TaSi2 under different pressures including band structures and density of states are reported. It turns out that TaSi2 should be metallic. The elastic constants Cij, bulk modulus B, shear modulus G, Young’s modulus E, Poisson’s ratio ν, B/G, Debye temperature θ, and wave velocities under pressures are also evaluated successfully. The calculated Cij obeys the Born–Huang stability criterion, which demonstrates that TaSi2 is mechanically stable under different pressures. More interestingly, the three-dimensional surface constructions and projections of E and B under different pressures are also systematically evaluated. With the increase of applied pressure, TaSi2 exhibits subtle anisotropy under zero pressure, and the anisotropy strengthened. Finally, the dependence of the thermodynamic properties on pressure/temperature is obtained and analyzed for the first time.

scholarly journals Mechanical Properties and Thermodynamic Parameters of Sr2 RuO4 and Sr2 RuO2 F2 Compounds under Pressure and Temperature Effects: Voigt–Reuss–Hill Approximations and Debye Model

2021 ◽  
pp. 1-8
Author(s):  
Meryem Ziati ◽  
◽  
Hamid Ez Zahraouy ◽  
Keyword(s):  
Thermodynamic Properties ◽  
Thermodynamic Parameters ◽  
Elastic Constants ◽  
Density Functional ◽  
Mechanical Stability ◽  
Poisson Ratio ◽  
Young Modulus ◽  
Debye Model ◽  
Full Potential ◽  
Pressure And Temperature Effects

We present a first-principles study of the elastic and thermodynamic properties of the Sr2 RuO4 -xFx alloy (x = 0, 2). Computations are carried out using the WIEN2K code based on a non-relativistic full–potential linearized augmented plane wave (FP-LAPW) method within the density functional theory (DFT). The Voigt–Reuss–Hill approximation method is applied to analyze the elastic constants, Poisson ratio, bulk, shear, and Young modulus at zero pressure and temperature using ELASTIC 1.0 software. The Sr2 RuO4 and Sr2 RuO2 F2 tetragonal phases are mechanically stable because the elastic constants satisfy Born’s mechanical stability condition. In addition, we performed a quasi-harmonic Debye model calculation using the GIBBS2 package to predict the thermodynamic properties and their temperature and pressure dependencies. Thermodynamic parameters such as the Gibbs free energy, heat capacity, Grüneisen parameter, and Debye temperature are successfully obtained and discussed

Structural, elastic and thermodynamic properties of A15-type compounds V3X (X = Ir, Pt and Au) from first-principles calculations

2016 ◽  
Vol 30 (35) ◽  
pp. 1650414 ◽  
Author(s):  
Mingliang Wang ◽  
Zhe Chen ◽  
Dong Chen ◽  
Cunjuan Xia ◽  
Yi Wu
Keyword(s):  
Thermodynamic Properties ◽  
Debye Temperature ◽  
First Principles ◽  
Density Functional ◽  
Coefficient Of Thermal Expansion ◽  
Local Density ◽  
Debye Model ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Experimental Values

The structural, elastic and thermodynamic properties of the A15 structure V3Ir, V3Pt and V3Au were studied using first-principles calculations based on the density functional theory (DFT) within generalized gradient approximation (GGA) and local density approximation (LDA) methods. The results have shown that both GGA and LDA methods can process the structural optimization in good agreement with the available experimental parameters in the compounds. Furthermore, the elastic properties and Debye temperatures estimated by LDA method are typically larger than the GGA methods. However, the GGA methods can make better prediction with the experimental values of Debye temperature in V3Ir, V3Pt and V3Au, signifying the precision of the calculating work. Based on the E–V data derived from the GGA method, the variations of the Debye temperature, coefficient of thermal expansion and heat capacity under pressure ranging from 0 GPa to 50 GPa and at temperature ranging from 0 K to 1500 K were obtained and analyzed for all compounds using the quasi-harmonic Debye model.

FIRST-PRINCIPLES HIGH-PRESSURE ELASTIC AND THERMODYNAMIC PROPERTIES OF TANTALUM

2011 ◽  
Vol 25 (10) ◽  
pp. 1393-1407 ◽  
Author(s):  
JING-HE WU ◽  
XIAN-LIN ZHAO ◽  
YOU-LIN SONG ◽  
GUO-DONG WU
Keyword(s):  
Thermodynamic Properties ◽  
Elastic Constants ◽  
First Principles ◽  
Equations Of State ◽  
Debye Model ◽  
Thermal Expansivity ◽  
Orbital Method ◽  
Full Potential ◽  
Body Centered Cubic ◽  
Theoretical Results

The all-electron full-potential linearized muffin-tin orbital method, by means of quasi-harmonic Debye model, is applied to investigate the elastic constant and thermodynamic properties of body-centered-cubic tantalum (bcc Ta). The calculated elastic constants of bcc Ta at 0 K is consistent with the previous experimental and theoretical results. Our calculations give the correct trends for the pressure dependence of elastic constants. By using the convenient quasi-harmonic Debye model, we refined the thermal equations of state. The thermal expansivity and some other thermal properties agree well with the previous experimental and theoretical results.

DFT study of electronic and thermodynamic properties of gold-rich intermetallic compounds, Ce2Au2Cd and CeAu4Cd2

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jyoti Sagar ◽  
Reetu Singh ◽  
Vijay Kumar ◽  
Sanjay Kumar ◽  
Manish P. Singh ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Mechanical Strength ◽  
Intermetallic Compounds ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Debye Model ◽  
Effect Of Temperature ◽  
Mechanical Resistance ◽  
Electronic Band ◽  
High Mechanical Strength

Abstract Gold-rich rare earth intermetallic compounds (viz. Ce2Au2Cd and CeAu4Cd2) show unusual magnetic and physical properties, and they have extensive applications in electronic and mechanical industries due to their good electronic and thermal behavior with high mechanical strength. In the present research article, to take full advantage of technological importance of these materials, we have investigated the structural, electronic and thermodynamic properties of Ce2Au2Cd and CeAu4Cd2 ternary intermetallic compounds using density functional theory (DFT). The electronic band structure and density of state calculations show that Ce-f orbital electrons provide metallic character to both the compounds with strong hybridization of Au-p and Cd-p orbitals at the Fermi level. The effect of temperature has been studied on the various thermodynamic parameters using the quasi-harmonic Debye model. Thermodynamic properties show that CeAu4Cd2 compound has larger mechanical resistance (or high mechanical strength or hardness) and smaller randomness compared to Ce2Au2Cd with respect to temperature.

scholarly journals Strain Conditions for the Inverse Heusler Type Fully Compensated Spin-Gapless Semiconductor Ti2MnAl: A First-Principles Study

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2091 ◽  
Author(s):  
Tie Yang ◽  
Liyu Hao ◽  
Rabah Khenata ◽  
Xiaotian Wang
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Study ◽  
Debye Model ◽  
Pressure Effects ◽  
First Principles Calculation ◽  
Strain Condition ◽  
Functional Theory ◽  
Future Work

In this work, we systematically studied the structural, electronic, magnetic, mechanical and thermodynamic properties of the fully compensated spin-gapless inverse Heusler Ti2MnAl compound under pressure strain condition by applying the first-principles calculation based on density functional theory and the quasi-harmonic Debye model. The obtained structural, electronic and magnetic behaviors without pressure are well consistent with previous studies. It is found that the spin-gapless characteristic is destroyed at 20 GPa and then restored with further increase in pressure. While, the fully compensated ferromagnetism shows a better resistance against the pressure up to 30 GPa and then becomes to non-magnetism at higher pressure. Tetragonal distortion has also been investigated and it is found the spin-gapless property is only destroyed when c/a is less than 1 at 95% volume. Three independent elastic constants and various moduli have been calculated and they all show increasing tendency with pressure increase. Additionally, the pressure effects on the thermodynamic properties under different temperature have been studied, including the normalized volume, thermal expansion coefficient, heat capacity at constant volume, Grüneisen constant and Debye temperature. Overall, this theoretical study presents a detailed analysis of the physical properties’ variation under strain condition from different aspects on Ti2MnAl and, thus, can provide a helpful reference for the future work and even inspire some new studies and lead to some insight on the application of this material.

Sign in / Sign up

Export Citation Format

Share Document