scholarly journals First Principles Calculations on Elastic, Thermodynamic and Electronic Properties of Co2Zr and Co2Ti at High Temperature and Pressure

2020 ◽  
Vol 10 (6) ◽  
pp. 2097
Author(s):  
Mi-An Xue ◽  
Xiaoli Yuan ◽  
Cheng Zhong ◽  
Peng Wan
Keyword(s):  
High Temperature ◽  
Electronic Properties ◽  
Debye Temperature ◽  
First Principles ◽  
Density Functional ◽  
Debye Model ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
High Temperature And Pressure ◽  
Temperature And Pressure

Co2Zr and Co2Ti are both cubic crystals with a Cu2Mg-type structure. The elastic, thermodynamic and electronic properties of the intermetallic compounds Co2Zr and Co2Ti are investigated by using ab initio plane-wave pseudopotential density functional theory (PWPDFT) and generalized gradient approximation (GGA) under high temperature and pressure. The partially calculated results are consistent with the available experimental data. The elastic properties of Co2Zr and Co2Ti under high pressure were first studied by first principles calculations. The results indicate that the elastic constants, elastic modulus and Poisson’s ratio are functions of pressure, indicating that the effect of pressure on the ductility and anisotropy is significant. The thermodynamic properties are also calculated by the quasi-harmonic Debye model. In the range of 0~100 GPa pressure and 0~1500 K temperature, the Debye temperature Θ, the heat capacity CV and the thermal expansion α vary with pressure and temperature. Co2Ti has a higher Debye temperature than Co2Zr under the same pressure. Decreasing temperature and increasing pressure have the same effects on CV and α. The electron density difference and density of states of Co2Zr and Co2Ti are finally investigated. The results show that both Co2Zr and Co2Ti are typically metal crystals but Co2Zr has greater covalence than Co2Ti.

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.

THERMAL PROPERTIES OF THE XB2(X = Ag, Au) COMPOUNDS: A FIRST-PRINCIPLES STUDY

2013 ◽  
Vol 27 (12) ◽  
pp. 1350046
Author(s):  
HAVVA BOGAZ OZISIK ◽  
KEMAL COLAKOGLU ◽  
ENGIN DELIGOZ
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Debye Model ◽  
First Principles Calculations ◽  
Correlation Effects ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation

The thermodynamic properties of AgB 2 and AuB 2 compounds in AlB 2 and OsB 2-type structures are investigated from first-principles calculations based on density functional theory (DFT) using projector augmented waves (PAW) potentials within the generalized gradient approximation (GGA) for modeling exchange-correlation effects, respectively. Specifically, using the quasi-harmonic Debye model, the effects of pressure and temperature, up to 100 GPa and 1400 K, on the bulk modulus, Debye temperature, thermal expansion, heat capacity and the Grüneisen parameter are calculated successfully and trends are discussed.

scholarly journals First-principles calculations of mechanical and thermodynamic properties of tetragonal Be12Ti

RSC Advances ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 5302-5312 ◽  
Author(s):  
Xiankun Liu ◽  
Qijie Feng ◽  
Bin Tang ◽  
Jian Zheng ◽  
Zhou Zheng ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermodynamic Properties ◽  
Plane Wave ◽  
First Principles ◽  
Harmonic Approximation ◽  
First Principles Calculations ◽  
High Temperature And Pressure ◽  
Temperature And Pressure

The elastic and thermodynamic properties of tetragonal Be12Ti under high temperature and pressure are investigated by first-principles calculations based on pseudopotential plane-wave DFT within the GGA and quasi-harmonic approximation (QHA).

Benefits of Ga, Ge and As substitution in Li2FeSiO4: a first-principles exploration of the structural, electrochemical and capacity properties

2020 ◽  
Vol 22 (26) ◽  
pp. 14712-14719
Author(s):  
Xiaotong Yan ◽  
Yuhua Hou ◽  
Shouhong Zheng ◽  
Youlin Huang ◽  
Wei Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Electrochemical Capacity ◽  
Fe Substitution

Herein, the feasibility of Fe substitution by Ga, Ge and As in Li2FeSiO4 in modulating its structural, mechanical, electrochemical, capacity and electronic properties was systematically studied via first-principles calculations based on density functional theory within the generalized gradient approximation with Hubbard corrections (GGA+U).

Electronic structure of cubic BaTbO3 from first-principles pseudopotential calculations

2006 ◽  
Vol 84 (2) ◽  
pp. 115-120 ◽  
Author(s):  
G Y Gao ◽  
K L Yao ◽  
Z L Liu
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Pseudopotential Calculations ◽  
Correlation Potential ◽  
Density Contour

First-principles calculations of the electronic structure are performed for cubic BaTbO3 using the plane-wave pseudopotential method within the framework of density functional theory and using the generalized gradient approximation for the exchange-correlation potential. Our calculations show that cubic BaTbO3 is metallic, and that this metallic character is mainly governed by the Tb 4f electrons and the hybridization between the Tb 5d and O 2p states. From the analysis of the density of states, band structure, and charge density contour, we find that the chemical bonding between Tb and O is covalent while that between Ba and TbO3 is ionic. PACS Nos.: 71.15.Mb, 71.20.-b

scholarly journals Structural and Electronic Properties of Orthorhombic Phase Bi2Se3 Based On First-Principles Study

2019 ◽  
Vol 16 (2) ◽  
pp. 77 ◽  
Author(s):  
Muhammad Zamir Mohyedin ◽  
Afiq Radzwan ◽  
Mohammad Fariz Mohamad Taib ◽  
Rosnah Zakaria ◽  
Nor Kartini Jaafar ◽  
...  
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Computer Code ◽  
First Principles Calculation ◽  
Generalized Gradient ◽  
Exchange Correlation ◽  
Percentage Difference ◽  
Structural And Electronic Properties

Bi2Se3 is one of the promising materials in thermoelectric devices and very useful out of environmental concern due to its efficiency to perform at room temperature. Based on the first-principles calculation of density functional theory (DFT) by using CASTEP computer code, structural and electronic properties of Bi2Se3 were investigated. The calculation is conducted within the exchange-correlation of local density approximation (LDA) and generalized gradient approximation within the revision of Perdew-Burke-Ernzerhof (GGA-PBE) functional. It was found that the results are consistent with previous works of theoretical study with small percentage difference. LDA exchange-correlation functional method is more accurate and have a better agreement than GGA-PBE to describe the structural properties of Bi2Se3 which consist of lattice parameters. LDA functional also shown more accurate electronic structure of Bi2Se3 that consist of band structure and density of states (DOS) which consistent with most previous theoretical works with small percentage difference. This study proves the reliability of CASTEP computer code and show LDA exchange-correlation functional is more accurate in describing the nature of Bi2Se3 compared to the other functionals.

Using First Principles Thermodynamics to Predict the Shape Surface Structure and Reactivity of Solvated Nanoparticles at High Temperatures and Pressures.

2013 ◽  
Vol 1546 ◽  
Author(s):  
Christopher J. O’Brien ◽  
Donald W. Brenner
Keyword(s):  
First Principles ◽  
Nanoparticle Synthesis ◽  
Surface Reactivity ◽  
Chemical Processes ◽  
First Principles Calculations ◽  
Chemical Potentials ◽  
High Temperature And Pressure ◽  
Bulk Thermodynamics ◽  
Pressure Water ◽  
Temperature And Pressure

ABSTRACTHydrothermal nanoparticle synthesis uses high temperature and pressure water to control the chemical processes that lead to specific compositions and structures. Analyses of the chemistry associated with this process have been mainly restricted to bulk thermodynamics in the form of quantities such as solubilities and empirical models based on experimental observations. In this paper we demonstrate for NiO and NiFe2O4 particles how effective reference chemical potentials derived from first principles calculations can be used to predict cluster shapes, nucleation barriers and surface reactivity. Implications for controlling the nanoparticle size and shape by adjusting pH and temperature will be discussed, as well as implications of these results in forming nanostructured materials by cluster condensation.

scholarly journals Carrier-mediated ferromagnetism in two-dimensional PtS2

RSC Advances ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 952-957 ◽  
Author(s):  
Konstantina Iordanidou ◽  
Michel Houssa ◽  
Clas Persson
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Hole Doping ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Impact

Using first principles calculations based on density functional theory the impact of hole doping on the magnetic and electronic properties of two dimensional PtS2 is studied.

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