ELASTIC, ELECTRONIC AND THERMODYNAMIC PROPERTIES OF Rh3X(X = Zr, Nb and Ta) INTERMETALLIC COMPOUNDS

Structural, electronic, elastic and thermodynamic properties of Rh 3 X ( X = Zr , Nb , Ta ) intermetallic compounds are investigated in the framework of density functional theory (DFT). The exchange-correlation (XC) potential is treated with the generalized gradient approximation (GGA) and local density approximation (LDA). The computed ground state properties agree well with the available theoretical and experimental values. The elastic constants are obtained by calculating the total energy versus volume conserving strains using Mehl model. The electronic and bonding properties are discussed from the calculations of band structures (BSs), densities of states and electron charge densities. The volume and bulk modulus at high pressure and temperature are investigated. Additionally, thermodynamic properties such as the heat capacity, thermal expansion and Debye temperature at high pressures and temperatures are also analyzed.

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

Modern Physics Letters B ◽

10.1142/s0217984916504145 ◽

2016 ◽

Vol 30 (35) ◽

pp. 1650414 ◽

Cited By ~ 6

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.

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Insight into Physical and Thermodynamic Properties of X3Ir (X = Ti, V, Cr, Nb and Mo) Compounds Influenced by Refractory Elements: A First-Principles Calculation

Crystals ◽

10.3390/cryst9020104 ◽

2019 ◽

Vol 9 (2) ◽

pp. 104 ◽

Cited By ~ 2

Author(s):

Dong Chen ◽

Jiwei Geng ◽

Yi Wu ◽

Mingliang Wang ◽

Cunjuan Xia

Keyword(s):

Thermodynamic Properties ◽

First Principles ◽

Density Functional ◽

Local Density ◽

First Principles Calculation ◽

Generalized Gradient ◽

Functional Theory ◽

Debye Temperatures ◽

Experimental Parameters ◽

Experimental Values

The effects of refractory metals on physical and thermodynamic properties of X3Ir (X = Ti, V, Cr, Nb and Mo) compounds were investigated using local density approximation (LDA) and generalized gradient approximation (GGA) methods within the first-principles calculations based on density functional theory. The optimized lattice parameters were both in good compliance with the experimental parameters. The GGA method could achieve an improved structural optimization compared to the LDA method, and thus was utilized to predict the elastic, thermodynamic and electronic properties of X3Ir (X = Ti, V, Cr, Nb and Mo) compounds. The calculated mechanical properties (i.e., elastic constants, elastic moduli and elastic anisotropic behaviors) were rationalized and discussed in these intermetallics. For instance, the derived bulk moduli exhibited the sequence of Ti3Ir < Nb3Ir < V3Ir < Cr3Ir < Mo3Ir. This behavior was discussed in terms of the volume of unit cell and electron density. Furthermore, Debye temperatures were derived and were found to show good consistency with the experimental values, indicating the precision of our calculations. Finally, the electronic structures were analyzed to explain the ductile essences in the iridium compounds.

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Thermodynamic Properties of CaSiO3 Perovskite at High Pressure and High Temperature

Zeitschrift für Naturforschung A ◽

10.1515/zna-2009-5-615 ◽

2009 ◽

Vol 64 (5-6) ◽

pp. 399-404 ◽

Cited By ~ 1

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.

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Structural, electronic and elastic properties of the B2-ScM (M =Au, Hg and Tl) intermetallic compounds: Ab initio calculations

International Journal of Computational Materials Science and Engineering ◽

10.1142/s2047684115500207 ◽

2015 ◽

Vol 04 (04) ◽

pp. 1550020

Author(s):

Ahmad A. Mousa ◽

Jamil M. Khalifeh

Keyword(s):

Mechanical Properties ◽

Bulk Modulus ◽

Intermetallic Compounds ◽

Elastic Constants ◽

Density Functional ◽

Electronic Band Structure ◽

Local Density ◽

Full Potential ◽

Generalized Gradient ◽

Electronic Band

Structural, electronic, elastic and mechanical properties of ScM (M[Formula: see text][Formula: see text][Formula: see text]Au, Hg and Tl) intermetallic compounds are studied using the full potential-linearized augmented plane wave (FP-LAPW) method based on the density functional theory (DFT), within the generalized gradient approximation (GGA) and the local density approximation (LDA) to the exchange-correlation approximation energy as implemented in the Wien2k code. The ground state properties including lattice parameters, bulk modulus and elastic constants were all computed and compared with the available previous theoretical and experimental results. The lattice constant was found to increase in contrast to the bulk modulus which was found to decrease with every substitution of the cation (M) starting from Au till Tl in ScM. Both the electronic band structure and density-of-states (DOS) calculations show that these compounds possess metallic properties. The calculated elastic constants ([Formula: see text], [Formula: see text] and [Formula: see text] confirmed the elastic stability of the ScM compounds in the B2-phase. The mechanical properties and ductile behaviors of these compounds are also predicted based on the calculated elastic constants.

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THERMODYNAMIC PROPERTIES OF MgSiO3 POST-PEROVSKITE

Modern Physics Letters B ◽

10.1142/s0217984910022391 ◽

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.

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Investigation of the structural, electronic, elastic and thermodynamic properties of Curium Monopnictides: An ab initio study

International Journal of Modern Physics B ◽

10.1142/s0217979217502265 ◽

2017 ◽

Vol 31 (30) ◽

pp. 1750226 ◽

Cited By ~ 4

Author(s):

H. Baaziz ◽

Dj. Guendouz ◽

Z. Charifi ◽

S. Akbudak ◽

G. Uğur ◽

...

Keyword(s):

Thermodynamic Properties ◽

Bulk Modulus ◽

Density Functional ◽

Local Density ◽

Structural Parameters ◽

Structural Phase ◽

Full Potential ◽

Generalized Gradient ◽

Metallic Behavior ◽

Spin Polarized

The structural, electronic, elastic and thermodynamic properties of Curium Monopnictides CmX (X = N, P, As, Sb and Bi) are investigated using first-principles calculations based on the density functional theory (DFT) and full potential linearized augmented plane wave (FP-LAPW) method under ambient condition and high pressure. The exchange-correlation term is treated using two approximations spin-polarized local density approximation (LSDA) and spin-polarized generalized gradient approximation generalized (GGA). The structural parameters such as the equilibrium lattice parameters, bulk modulus and the total energies are calculated in two phases: namely NaCl (B1) and CsCl (B2). The obtained results are compared with the previous theoretical and experimental results. A structural phase transition from B1 phase to B2 phase for Curium pnictides has been obtained. The highest transition pressure is 122 GPa for CmN and the lowest one is 10.0 GPa for CmBi compound. The electronic properties show that these materials exhibit half-metallic behavior in both phases. The magnetic moment is found to be around 7.0 [Formula: see text]B. The mechanical properties of CmX (X = N, P, As, Sb and Bi) are predicted from the calculated elastic constants. Our calculated results are in good agreement with the theoretical results in literature. The effect of pressure and temperature on the thermodynamic properties like the cell volume, bulk modulus and the specific heats C[Formula: see text] and C[Formula: see text], the entropy [Formula: see text] and the Grüneisen parameter [Formula: see text] have been foreseen at expanded pressure and temperature ranges.

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Extreme pressure conditions of bas based materials: Detailed study of structural changes, band gap engineering, elastic constants and mechanical properties

Processing and Application of Ceramics ◽

10.2298/pac1904401z ◽

2019 ◽

Vol 13 (4) ◽

pp. 401-410

Author(s):

Dejan Zagorac ◽

Jelena Zagorac ◽

Klaus Doll ◽

Maria Cebela ◽

Branko Matovic

Keyword(s):

Mechanical Properties ◽

Band Gap ◽

Elastic Constants ◽

Density Functional ◽

Structural Changes ◽

High Pressures ◽

Local Density ◽

Structure Property ◽

Generalized Gradient ◽

Band Gap Engineering

A Density Functional Theory (DFT) study has been performed in order to investigate behaviour of barium sulfide (BaS) at high pressures, and relationship between computed properties, in great detail. Novel predicted and previously synthesized BaS modifications have been calculated using Local Density Approximations (LDA) and Generalized Gradient Approximation (GGA) functionals. In particular, a detailed investigation of structural changes and its corresponding volume effect up to 100GPa, with gradual pressure increase, has been performed from the first principles. Band gap engineering of the experimentally observed BaS phases at high pressures has been simulated and structure-property relationship is investigated. For each of the predicted and experimentally observed BaS structures, elastic constants and mechanical properties under compression have been investigated (e.g. ductility/brittleness, hardness, anisotropy). This study offers a new perspective of barium sulphide as a high pressure material with application in ceramics, optical and electrical technologies.

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

Canadian Journal of Physics ◽

10.1139/cjp-2016-0299 ◽

2016 ◽

Vol 94 (9) ◽

pp. 865-876 ◽

Cited By ~ 2

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.

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PHASE TRANSITION, ELASTIC AND THERMODYNAMIC PROPERTIES OF BERYLLIUM VIA FIRST PRINCIPLES

International Journal of Modern Physics B ◽

10.1142/s0217979213501300 ◽

2013 ◽

Vol 27 (24) ◽

pp. 1350130 ◽

Cited By ~ 3

Author(s):

YAN CHENG ◽

HAI-HUA CHEN ◽

FAN-XIANG XUE ◽

GUANG-FU JI ◽

MIN GONG

Keyword(s):

Phase Transition ◽

Thermodynamic Properties ◽

First Principles ◽

Density Functional ◽

High Pressures ◽

Intermediate Phase ◽

Linear Thermal Expansion ◽

Generalized Gradient ◽

Functional Theory ◽

Bcc Phase

The phase transition, elastic and thermodynamic properties of beryllium (Be) have been studied at high pressures by plane-wave ultrasoft pseudopotential density functional theory (DFT) within the generalized gradient approximation (GGA). It is found that the hcp → bcc phase transition of Be occurs at 506 GPa (T = 0 K ) and occurs at 1200 K (P = 0 GPa ). The coefficients of linear thermal expansion of the hexagmal close-packed (hcp), bcc and orthorhombic Be have been calculated. The hcp → orthorhombic → bcc phase transitions do not occur in all range of pressures, that is to say, the orthorhombic Be is not an intermediate phase between the hcp and bcc Be. The obtained bulk modulus (B0) are 113.2 GPa (for hcp Be), 113.1 GPa (for bcc Be) and 70.5 GPa (for orthorhombic Be), respectively.

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First-Principles Calculations on Crystal Structure and Thermodynamic Properties of Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.2517 ◽

2007 ◽

Vol 336-338 ◽

pp. 2517-2520

Author(s):

Yue Zhang ◽

Xue Gao ◽

Jia Xiang Shang ◽

Xiao Ping Han

Keyword(s):

Thermodynamic Properties ◽

First Principles ◽

Density Functional ◽

Alloy Element ◽

Material System ◽

First Principles Calculations ◽

Densities Of States ◽

Potential Applications ◽

Bonding Properties ◽

New Material

First-principles calculations have been widely used to describe the ground state properties of materials over almost 20 years. Recently, a great progress was made in the first-principle calculations. Thermodynamic properties can also be gotten by calculations of the phonon densities of states (phonon DOS) and phonon dispersions of materials, which show widely potential applications in material researches. In the present work, the energetics and bonding properties of interfaces between ZrO2 and Ni metal were given by first-principles calculations. The results show that alloy element impurities (Al, Cr and Y) influence remarkably the adhesion of the ceramic and metal. On the other hand, the phonon densities of states and phonon dispersions of ZrO2 were calculated with density functional perturbation theory. From the phonon DOS, the thermodynamic properties were derived and the phase transformation of ZrO2 was discussed. By this method, the thermodynamic properties of material can be gotten from atom and electron levels without any experiment data. It is a new approach to design and study the thermodynamic properties in new material system.

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