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

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.

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.

Hydrogenation as a source of superconductivity in two-dimensional TiB2

2021 ◽  
pp. 2150057
Author(s):  
Hui Wang ◽  
Chen Pan ◽  
Sheng-Yan Wang ◽  
Hong Jiang ◽  
Yin-Chang Zhao ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Vibration Frequency ◽  
First Principles ◽  
Density Functional ◽  
Tensile Strain ◽  
2D Materials ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Density Functional Perturbation Theory ◽  
Potential Applications

Using first-principles calculations based on density functional perturbation theory, we demonstrate hydrogenation-induced superconductivity in monolayer TiB2H. Hydrogen adatoms destroy the Dirac state of monolayer TiB2 and monolayer TiB2H has a high vibration frequency. Monolayer TiB2H is a phonon-mediated superconductor. Monolayer TiB2H has a predicted [Formula: see text] of 8[Formula: see text]K, which further increases under external tensile strain. Thus, this study extends our understanding of superconductivity in two-dimensional (2D) materials and its potential applications.

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

2014 ◽  
Vol 28 (03) ◽  
pp. 1450006 ◽  
Author(s):  
M. OULD KADA ◽  
T. SEDDIK ◽  
A. SAYEDE ◽  
R. KHENATA ◽  
A. BOUHEMADOU ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Intermetallic Compounds ◽  
Density Functional ◽  
High Pressures ◽  
Local Density ◽  
Generalized Gradient ◽  
Charge Densities ◽  
Densities Of States ◽  
Bonding Properties ◽  
Experimental Values

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.

Theoretical calculations of stability, mechanical and thermodynamic properties of IVA group Willemite-II nitrides

2015 ◽  
Vol 14 (04) ◽  
pp. 1550024 ◽  
Author(s):  
Ying-Chun Ding ◽  
Min Chen ◽  
Wen-Juan Wu
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Mechanical Anisotropy ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Good Agreement

The structural stability and mechanical and thermodynamic properties of WII- A 3 N 4 ( A=C , Si , Ge and Sn ) are calculated by first-principles calculations based on the density functional theory. The calculated lattice parameters and elastic constants of WII- A 3 N 4 ( A=C , Si , Ge and Sn ) are in good agreement with the experimental data and previously calculated values. WII- A 3 N 4 ( A=C , Si , Ge and Sn ) compounds are also found to be thermodynamically and mechanically stable. The results suggest that hardness of WII- C 3 N 4 is the hardest of these C 3 N 4 polymorphs. The hardness of WII- Sn 3 N 4 is the smallest among WII- A 3 N 4 ( A=C , Si , Ge and Sn ). Furthermore, the mechanical anisotropy, Debye temperature, the minimum thermal conductivity and thermodynamic properties of WII- A 3 N 4 ( A=C , Si , Ge and Sn ) compounds can be investigated.

scholarly journals Me-graphane: tailoring the structural and electronic properties of Me-graphene via hydrogenation

2021 ◽  
Author(s):  
Enesio Marinho Jr ◽  
Pedro Alves da Silva Autreto
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Large Family ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Potential Applications

Graphene-based materials (GBMs) are a large family of materials that have attracted great interest due to potential applications. In this work, we applied first-principles calculations based on density functional theory...

scholarly journals Electronic and optical properties of Ba(1-x)Ca(x) TiO3 and Ba(1-x)Sr(x)TiO3

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
A. Belaaraj ◽  
O. Tahiri ◽  
S. Kassou ◽  
R. El Mrabet
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Low Energy ◽  
Band Gaps ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Densities Of States ◽  
Indirect Band Gap

The effect of Ca and Sr-doping on the structural electronic and optical properties of the cubic Ba1-xCaxTiO3 and Ba1-xSrxTiO3 (x=0.4, 0.6) mixed crystals was investigated using first-principles calculations based on density functional theory (DFT). The calculated band structures based on the optimized geometry of the cell for the solid solutions show an indirect band gap character at M-points, with low energy dispersion along height symmetry directions in the Brillouin zone. The band gaps increase with Ca and Sr concentrations. The total and partial densities of states were analyzed to examine the contribution of different orbitals to the maximum of valence band and the minimum of the conduction band. The optical properties such as reflectivity, energy loss, refractive index and extinction coefficient were studied. #DFT_calculations #band_gap #density_of_states #optical_properties

First-Principles Investigations on Electronic, Elastic and Thermodynamic Properties of VN under High Pressure

2012 ◽  
Vol 550-553 ◽  
pp. 2805-2809 ◽  
Author(s):  
Ai Min Hao ◽  
Xiao Cui Yang ◽  
Li Xin Zhang ◽  
Qi Zhou Zhang
Keyword(s):  
High Pressure ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
Structural Phase ◽  
Basis Set ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Elevated Pressures ◽  
Cscl Type

An investigation on electronic, elastic and thermodynamic properties of VN under high pressure has been conducted using first-principles calculations based on density functional theory (DFT) with the plane wave basis set as implemented in the CASTEP code. At elevated pressures VN is predicted to undergo a structural phase transition from the relatively open NaCl-type structure into the denser CsCl-type atomic arrangement. The predicted transition pressure is 189 GPa. The elastic constants, Debye temperature as a function of pressure and temperature of VN are presented.

The structural, electronic, mechanical, lattice dynamics and thermodynamic properties of Rh5B4: First-principles calculations

2017 ◽  
Vol 31 (27) ◽  
pp. 1750245
Author(s):  
Yong Guo ◽  
Tao Gao ◽  
Shizhang Li
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
Direct Method ◽  
Ambient Pressure ◽  
Vibrational Entropy ◽  
First Principles Calculations ◽  
Metallic Behavior ◽  
Phonon Contribution ◽  
The Density Functional Theory

The structural, electronic, vibrational, mechanical and thermodynamic properties of Rh5B4 have been investigated within the framework of the density functional theory (DFT) and the direct method using first-principles calculations. The calculated lattice parameters are in good agreement with the available experimental data. The electronic structure suggests that Rh5B4 should exhibit the metallic behavior and hybridizations exist between Rh-d and B-s, B-p orbitals, which illuminates that the bonding between them has certain covalent character. Mechanical properties including elastic constants, bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio [Formula: see text] are calculated. Phonon dispersions and phonon density of states (DOS) are obtained, respectively. Our results indicate that Rh5B4 is dynamically and mechanically stable with better ductility (B/G = 3.28) at ambient pressure. In addition, the phonon frequencies at the center ([Formula: see text] point) of the first Brillouin zone are predicted and Raman-active and infrared-active modes are also assigned. Finally, the phonon contribution to the Helmholtz free energy F, the phonon contribution to the internal energy E, the constant volume specific heat Cv and vibrational entropy S are studied over the range 0 [Formula: see text] 1000 K.

First-Principles Investigations of Electronic, Dynamic and Thermodynamic Properties of α-MnO2

2014 ◽  
Vol 936 ◽  
pp. 591-595 ◽  
Author(s):  
Ai Min Hao ◽  
Na Qi Wang
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Dynamic Properties ◽  
Thermodynamic Quantities ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Direct Band Gap ◽  
Direct Band

We investigate the electronic, dynamic and thermodynamic properties of α-MnO2 using first-principles calculations based on density functional theory (DFT) with the GGA+U method. The results of electronic structures show that α-MnO2is a semiconductor with a direct band gap of 1.4 eV at Γ point. The results of dynamic properties indicate that the structure of α-MnO2 is dynamically unstable at ground-state. Several important thermodynamic quantities, such as entropy, enthalpy and Gibbs free energy, et al each as a function of temperature were presented.

STRUCTURAL AND ELECTRONIC PROPERTIES OF Pd AND Au MONOLAYERS ADSORBED ON MoS2: A COMPARATIVE STUDY FROM DFT CALCULATIONS

2018 ◽  
Vol 25 (06) ◽  
pp. 1850117
Author(s):  
PING WU ◽  
NAIQIANG YIN ◽  
WENJING CHENG ◽  
PENG LI
Keyword(s):  
Fermi Level ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Electrode Materials ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Potential Applications ◽  
Work Functions

The morphology, stability and electronic properties of Pd and Au monolayers supported by MoS2 substrate have been investigated by using the first principles calculations based on periodic density functional theory (DFT). The results demonstrated that the most stable site is top of Mo top of S ([Formula: see text]) for the adsorption of Pd and Au monolayers on MoS2. We found that Pd/MoS2 with lower adsorption energy of [Formula: see text]0.54[Formula: see text]eV is energetically more stable than Au/MoS2. Due to the emergence of impurities state in the bandgap of MoS2, Pd/MoS2 and Au/MoS2 display metallic character upon coating of metal monolayers. We demonstrated that the Pd monolayer strongly hybrids with underlying Mo and S around the Fermi level, which is achieved by the intermediate Pd–S–Mo hybridized chains. On the contrary, intensity of impurities states around the fermi level is much weaker for Au/MoS2, which can be explained by weak hybridizations between sp state of Au and 4[Formula: see text] state of nearest neighboring Mo. The calculated results demonstrated that work functions are markedly modulated to 4.99 and 6.23[Formula: see text]eV after coating of Pd and Au monolayer, respectively, which can be qualitatively explained by the fact that Pd (as accepter) received charge from the MoS2 host, while Au donated charge to the host. These findings promise potential applications in the fields of nanoelectronics in future, such as it's helpful to choose suitable electrode materials for MoS2-based nanodevices.

Sign in / Sign up

Export Citation Format

Share Document