scholarly journals Structural, Electronic, Magnetic, Mechanic and Thermodynamic Properties of the Inverse Heusler Alloy Ti2NiIn Under Pressure

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 429 ◽  
Author(s):  
Tie Yang ◽  
Jieting Cao ◽  
Xiaotian Wang
Keyword(s):  
Thermodynamic Properties ◽  
Heusler Alloy ◽  
Density Functional ◽  
Mechanical Stability ◽  
Electronic Band Structure ◽  
Debye Model ◽  
Half Metallicity ◽  
Electronic Band ◽  
Functional Theory ◽  
Valence Electrons

Structural, electronic, magnetic and mechanic properties of the inverse Heusler alloy Ti2NiIn under different pressure are systematically studied with density functional theory (DFT). The equilibrium lattice constant and electronic band structure at null pressure are obtained to be consistent with previous work. Under currently applied static pressure from 0 GPa to 50 GPa, it is found that the half-metallicity of the material is maintained and the total magnetic moment (Mt) is kept at 3 µB, which obeys the Slater–Pauling rule, Mt = Zt − 18, where Zt is the total number of valence electrons. Besides, the effect of the tetragonal distortion was studied and it is found that the magnetic property of Ti2NiIn is almost unchanged. Several mechanical parameters are calculated including three elastic constants, bulk modulus B, Young’s modulus E, and shear modulus S and the mechanical stability is examined accordingly. Furthermore, the thermodynamic properties, such as the heat capacity CV, the thermal expansion coefficient α, the Grüneisen constant γ and the Debye temperature ΘD, are computed by using the quasi-harmonic Debye model within the same pressure range at a series of temperature from 0 to 1500 K. This theoretical study provides detailed information about the inverse Heusler compound Ti2NiIn from different aspects and can further lead some insight on the application of this material.

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.

Electronic structure, optical and thermodynamic properties of ternary hydrides MBeH3 (M = Li, Na, and K)

2016 ◽  
Vol 94 (9) ◽  
pp. 865-876 ◽  
Author(s):  
Dj Guendouz ◽  
Z. Charifi ◽  
H. Baaziz ◽  
T. Ghellab ◽  
N. Arikan ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Thermodynamic Properties ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Debye Model ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Electron Charge Density ◽  
Principal Aspect

Electronic band structure, optical and thermodynamic properties of ternary hydrides MBeH3 (M = Li, Na, and K) were studied using ab initio density functional theory (DFT). The effect of the adopted approximation to the exchange-correlation functional of the DFT is explicitly investigated by considering four different expressions of two different classes (local-density approximation and generalized-gradient approximation). The calculated magnitude of B classifies MBeH3 (M = Li, Na, and K) as easily compressible materials. The bonding interaction in these compounds is quite complicated. The interaction between M and BeH6 is ionic and that between Be and H comprises both ionic and covalent characters. The electronic structure of the complex hydride was investigated by calculating the partial and total densities of states, and electron charge density distribution. Large gaps in the density of states appear at the Fermi energy of LiBeH3, NaBeH3, and KBeH3 indicating that these classes of hydrides are insulators. Optical properties, including the dielectric function, reflectivity, and absorption coefficient, each as a function of photon energy, are calculated and show an optical anisotropy for LiBeH3 and KBeH3. Through the quasi-harmonic Debye model, in which the phononic effects are considered, temperature dependence of volume V(T), bulk modulus B(T), and thermal expansion coefficient α(T), constant-volume and constant-pressure specific heat (Cv and Cp) and Debye temperature ΘD, the entropy S, and the Grüneisen parameter γ were calculated at wide pressure and temperature ranges. The principal aspect of the obtained results is the close similarity of MBeH3 (M = Li, Na, and K) compounds.

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.

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.

Magnetism and Half-Metallicity in (100) Surface of Inverse Heusler Mn2CoSb

2014 ◽  
Vol 1015 ◽  
pp. 377-380
Author(s):  
Tao Chen ◽  
Ying Chen ◽  
Yin Zhou ◽  
Hong Chen
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
First Principles ◽  
Heusler Alloy ◽  
Density Functional ◽  
Magnetic Moments ◽  
Surface States ◽  
First Principles Calculations ◽  
Half Metallicity ◽  
Functional Theory

Using the first-principles calculations within density functional theory (DFT), we investigated the electronic and magnetic properties of (100) surface of inverse Heusler alloy Mn2CoSb with five different terminations. Our work reveals that the surface Mn atom moves to vacuum while surface Co atom moves to slab. Moreover, duo to the reason that the surface atom lost half of the nearest atoms with respect to the bulk phase, resulting in the decrease of hybridization, the atom-resolved spin magnetic moments of surface atoms are enhanced. Further investigation on DOS and PDOS showed that half-metallicity was preserved only in SbSb-termination while was destroyed in MnCo-, MnSb-, MnMn-, and CoCo-termination due to the appearance of surface states.

Thermodynamic Properties of CaSiO3 Perovskite at High Pressure and High Temperature

2009 ◽  
Vol 64 (5-6) ◽  
pp. 399-404 ◽  
Author(s):  
Zi-Jiang Liu ◽  
Xiao-Ming Tan ◽  
Yuan Guo ◽  
Xiao-Ping Zheng ◽  
Wen-Zhao Wu
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
High Pressures ◽  
Local Density ◽  
Harmonic Approximation ◽  
Debye Model ◽  
Functional Theory ◽  
Casio3 Perovskite ◽  
First Time

The thermodynamic properties of tetragonal CaSiO3 perovskite are predicted at high pressures and temperatures using the Debye model for the first time. This model combines the ab initio calculations within local density approximation using pseudopotentials and a plane wave basis in the framework of density functional theory, and it takes into account the phononic effects within the quasi-harmonic approximation. It is found that the calculated equation of state is in excellent agreement with the observed values at ambient condition. Based on the first-principles study and the Debye model, the thermal properties including the Debye temperature, the heat capacity, the thermal expansion and the entropy are obtained in the whole pressure range from 0 to 150 GPa and temperature range from 0 to 2000 K.

Pressure effect on the structural, phonon, elastic and thermodynamic properties of L12phase RH3TA: First-principles calculations

2018 ◽  
Vol 32 (14) ◽  
pp. 1850169
Author(s):  
Leini Wang ◽  
Zhang Jian ◽  
Wei Ning
Keyword(s):  
Thermodynamic Properties ◽  
Density Functional ◽  
Harmonic Approximation ◽  
Debye Model ◽  
Approximation Model ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Relationship Of ◽  
G Ratio ◽  
Wide Pressure

The phonon, elastic and thermodynamic properties of L12phase Rh3Ta have been investigated by the density functional theory (DFT) approach combined with the quasi-harmonic approximation model. The results of the phonon band structure show that L12phase Rh3Ta possesses dynamical stability in the pressure range from 0–80 GPa due to the absence of imaginary frequencies. The pressure dependences with the elastic constants C[Formula: see text], shear modulus G, bulk modulus B, Young’s modulus Y, Poisson’s ratio and B/G ratio have been analyzed. The results of the elastic properties studies show that L12phase Rh3Ta compound is mechanically stable and possesses a higher hardness, improved ductility and plasticity under higher pressures. The pressure and temperature relationship of the thermodynamic properties, such as the Debye temperature [Formula: see text], heat capacity C[Formula: see text], thermal expansion coefficient [Formula: see text] and the Grüneisen parameter [Formula: see text] are predicted by the quasi-harmonic Debye model in a wide pressure (0–80 GPa) and temperature (0–750 K) ranges.

THERMODYNAMIC PROPERTIES OF MgSiO3 POST-PEROVSKITE

2010 ◽  
Vol 24 (03) ◽  
pp. 315-324
Author(s):  
ZI-JIANG LIU ◽  
XIAO-WEI SUN ◽  
CAI-RONG ZHANG ◽  
LI-NA TIAN ◽  
YUAN GUO
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
High Pressures ◽  
Local Density ◽  
Harmonic Approximation ◽  
Debye Model ◽  
Functional Theory ◽  
High Pressures And Temperatures ◽  
First Time

The thermodynamic properties of MgSiO 3 post-perovskite are predicted at high pressures and temperatures using the Debye model for the first time. This model combines with ab initio calculations within local density approximation using pseudopotentials and a plane wave basis in the framework of density functional theory, and it takes into account the phononic effects within the quasi-harmonic approximation. It is found that the calculated equation of state of MgSiO 3 post-perovskite is in excellent agreement with the latest observed values. Based on the first-principles study and the Debye model, the thermal properties including the Debye temperature, the heat capacity, the thermal expansion, and the entropy are obtained in the whole pressure range from 0 to 150 GPa and temperature range from 0 to 2000 K.

Study of Thermodynamic Properties of Superhard w-BC2N

2013 ◽  
Vol 750-752 ◽  
pp. 1141-1145
Author(s):  
Ai Ling Ding ◽  
Feng Li ◽  
Chun Mei Li ◽  
Jing Ao ◽  
Zhi Qian Chen
Keyword(s):  
Density Functional Theory ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Density Functional ◽  
Local Density ◽  
Density Functional Theory Method ◽  
Debye Model ◽  
Theory Method ◽  
Density Approximation ◽  
Functional Theory

We investigate the thermodynamic properties of superhard w-BC2N by using ab initio plane-wave pseudopotential density functional theory method within local density approximation (LDA). Through the quasi-harmonic Debye model, we investigate the thermodynamic properties of w-BC2N. The variation of the thermal expansion, the heat capacity and the Gruneisen parameter γ with pressure P and temperature T, and many other thermodynamic parameters of w-BC2N are obtained systematically.

scholarly journals Structural, Electronic and Vibrational Properties of YAl3(BO3)4

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 545 ◽  
Author(s):  
Aleksandr S. Oreshonkov ◽  
Evgenii M. Roginskii ◽  
Nikolai P. Shestakov ◽  
Irina A. Gudim ◽  
Vladislav L. Temerov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Band Gap ◽  
Density Functional ◽  
Dielectric Material ◽  
Electronic Band Structure ◽  
Vibrational Properties ◽  
Electronic Band ◽  
Functional Theory ◽  
Dynamical Properties ◽  
Indirect Band Gap

The crystal structure of YAl3(BO3)4 is obtained by Rietveld refinement analysis in the present study. The dynamical properties are studied both theoretically and experimentally. The experimental Raman and Infrared spectra are interpreted using the results of ab initio calculations within density functional theory. The phonon band gap in the Infrared spectrum is observed in both trigonal and hypothetical monoclinic structures of YAl3(BO3)4. The electronic band structure is studied theoretically, and the value of the band gap is obtained. It was found that the YAl3(BO3)4 is an indirect band gap dielectric material.

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