Mechanical and thermodynamic properties of AlX (X = N, P, As) compounds

2017 ◽  
Vol 31 (23) ◽  
pp. 1750167 ◽  
Author(s):  
Lifang Xu ◽  
Wei Bu
Keyword(s):  
Thermodynamic Properties ◽  
Specific Heat ◽  
Atomic Number ◽  
Phonon Dispersion ◽  
Theoretical Data ◽  
Constant Volume ◽  
Vibrational Entropy ◽  
Debye Temperatures ◽  
The Difference ◽  
Good Agreement

The Vickers hardness of various AlX (X = N, P, As) compound polymorphs were calculated with the bond resistance model. Thermodynamic properties, such as vibrational entropy, constant volume specific heat and Debye temperatures, were calculated using phonon dispersion relations and phonon density of states (DOS). The calculated values are in good agreement with the previous experimental and theoretical data. For the same structure of AlX (X = N, P, As) compounds, their hardness and Debye temperatures both decrease with the X atomic number. The wurtzite (wz) and zincblende (zb) structures of the same compounds AlX share an almost identical hardness, but have different Debye temperatures. The difference between wz and zb structures increases as the atomic number of X increases. The thermodynamic properties reveal that the constant volume specific heat approaches the Dulong–Petit rule at high temperatures.

THE AB INITIO CALCULATION OF THE DYNAMICAL AND THE THERMODYNAMIC PROPERTIES OF THE ZINC-BLENDE GaX (X=N, P, As AND Sb)

2012 ◽  
Vol 01 (03) ◽  
pp. 1250026
Author(s):  
Y. BOUHADDA ◽  
A. BENTABET ◽  
N. E. FENINECHE ◽  
Y. BOUDOUMA
Keyword(s):  
Thermodynamic Properties ◽  
Specific Heat ◽  
Ab Initio ◽  
Lattice Dynamics ◽  
Phonon Frequency ◽  
Harmonic Approximation ◽  
Simulation Method ◽  
Constant Volume ◽  
Zinc Blende ◽  
Good Agreement

By this work, we aim to study the dynamical and the thermodynamic properties of the zinc-blende GaX ( X = N , P , As and Sb ) using the Ab initio simulation method. Indeed, we studied the lattice dynamics, the constant-volume specific heat (Cv), the internal energy (U), the entropy (S) and the free energy (F). The observed differences between the properties of GaX elements were discussed. Our results and the available literature data (theoretical and experimental) seems to be in good agreement. Moreover, Cv, U, F and S were calculated by using the harmonic approximation in the calculation of the dynamic lattice vibration. The good agreement between our results of both the phonon frequency, the constant-volume specific heat and the experimental data allows us to conclude that our results of S, U and F of GaX were well predicted.

High Pressure Structural and Mechanical Properties of YBi and ScBi Compounds

2016 ◽  
Vol 1141 ◽  
pp. 39-43 ◽  
Author(s):  
Ashok K. Ahirwar ◽  
Mahendra Aynyas ◽  
Yeshvir Singh Panwar ◽  
Sankar P. Sanyal
Keyword(s):  
Phase Transition ◽  
Theoretical Study ◽  
Structural Phase ◽  
Theoretical Data ◽  
Second Order ◽  
Mechanical And Thermal Properties ◽  
First Order ◽  
Debye Temperatures ◽  
Phase Transition Pressure ◽  
Good Agreement

A theoretical study of first order pressure induced structural phase transition, mechanical and thermal properties of YBi and ScBi compounds have been investigated using the modified inter-ionic potential theory (MIPT), which parametrically includes the effect of coulomb screening. The calculated results of phase transition pressure of ScBi and YBi are agree well with the available theoretical data. We have also reported the second order elastic constants and Debye temperature of these compounds. Our calculated values of second order elastic constant C11, C12 and C44 are 128.4, 29.5, 30.2 GPa and 123.1, 29.7, 30.3 GPa for ScBi and YBi compounds respectively. These results are in good agreement with available theoretical data. We have also estimated Debye temperatures (θD) are 80K, 86K, for ScBi and YBi compounds respectively.

Estimation of the heat capacity of CdTe semiconductor

2016 ◽  
Vol 30 (04) ◽  
pp. 1650026 ◽  
Author(s):  
Hüseyin Koç ◽  
Erhan Eser
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Binomial Coefficient ◽  
Debye Model ◽  
The Other ◽  
Temperature Range ◽  
Theoretical Results ◽  
Good Agreement

The aim of this paper is to provide a simple and reliable analytical expression for the thermodynamic properties calculated in terms of the Debye model using the binomial coefficient, and examine specific heat capacity of CdTe in the 300–1400 K temperature range. The obtained results have been compared with the corresponding experimental and theoretical results. The calculated results are in good agreement with the other results over the entire temperature range.

Thermodynamic Properties of Wurtzite and Zinc-Blende AlN

2013 ◽  
Vol 455 ◽  
pp. 127-130
Author(s):  
Xue Mei Cai ◽  
Jing Mei Wang ◽  
Qian Neng Zhou
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Room Temperature ◽  
Potential Method ◽  
Zinc Blende ◽  
Phonon Spectra ◽  
The Difference ◽  
Increasing Temperature ◽  
Pseudo Potential ◽  
Good Agreement

In this paper, we carry out linear response calculation to determine the phonon density of states and the thermodynamic properties of the wurtzite and zinc-blende AlN by using the norm-conserving pseudo-potential method. The optimized lattice constant is in good agreement with the available experimental data. The internal energies increase almost linearly with temperature and the phonon free energy curves move down with increasing temperature in both structures. The zero value of the lattice vibration free energy appears at temperature 707K in wurtzite and 728K in zinc-blende AlN respectively. The specific heat capacity of the wurtzite AlN is higher than that of the zinc-blende AlN at room temperature owing to the difference of the phonon spectra.

Alloying-related trends in thermal properties of ternary TiN-based nitrides

2014 ◽  
Vol 28 (15) ◽  
pp. 1450087 ◽  
Author(s):  
Shuo Huang ◽  
Rui-Zi Li ◽  
San-Tao Qi ◽  
Bao Chen ◽  
Jiang Shen
Keyword(s):  
Thermal Properties ◽  
Melting Point ◽  
First Principles ◽  
Theoretical Data ◽  
Vibrational Entropy ◽  
First Principles Calculations ◽  
Alloying Element ◽  
Band Filling ◽  
Solute Species ◽  
Good Agreement

The thermal properties of TiN -based nitrides are studied using first-principles calculations. Bulk modulus, thermal expansion, heat capacity, vibrational entropy and melting point for TiN –X compounds are computed, considering all possible transition-metal solute species X. The calculated properties show clear trends as a function of d-band filling. The results indicate that the largest increase of melting point of TiN is caused by alloying element W. Computed thermal properties for pure TiN are in good agreement with the available experimental and theoretical data.

scholarly journals Thermodynamic properties of CO 2 up to 3000 atmospheres between 25 and 150°C

1937 ◽  
Vol 160 (902) ◽  
pp. 376-384 ◽  
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Total Energy ◽  
Specific Heat ◽  
Interpolation Formula ◽  
Constant Volume ◽  
Present Communication ◽  
Different Temperatures

In previous papers (Michels and Michels 1935; Michels, Michels and Wouters 1935) the results of isotherm measurements on CO 2 and a method for interpolation of the pv values at intermediate temperatures and densities have been published. From the data obtained, the specific heat at constant volume C v , the free energy F , the total energy U , and the entropy S , have been calculated, and these results are given in the present communication. The values of F, U and S at N. T. P. have been taken as zero. The values of C v , F, S and U at a density of 1 Amagat unit ( ρ = 1) have first been calculated for different temperatures. To the values, so obtained, has been added the increase of these quantities by compression. The values of C v at ρ = 1 have been calculated, using the interpolation formula as given by Shilling and Partington (1928).

Angular Forces and Normal Vibrations in Platinum

1977 ◽  
Vol 32 (12) ◽  
pp. 1490-1494
Author(s):  
H. L. Kharoo ◽  
O. P. Gupta ◽  
M. P. Hemkar
Keyword(s):  
Phonon Dispersion ◽  
Inelastic Neutron Scattering ◽  
Sampling Technique ◽  
Inelastic Neutron ◽  
Dynamical Study ◽  
Normal Vibrations ◽  
Specific Heats ◽  
Debye Temperatures ◽  
Root Sampling ◽  
Good Agreement

Abstract A lattice dynamical study of platinum has been made on the basis of the improved Clark-Gazis-Wallis model considering volume forces of Krebs' nature. The phonon dispersion relations obtained for the three symmetry directions have been compared with the recent inelastic neutron scattering experiments. The specific heat at constant volume has been calculated by Blackman's root sampling technique for temperatures above Θ/10, and below this temperature the calculations are carried out by employing the modified Houston spherical six-term integration procedure. The computed lattice specific heats in terms of the effective Debye temperatures Θ are compared with the available calorimetric data. The theory is in good agreement with the experimental data.

Mechanical, electronic and thermodynamic properties of full Heusler compounds Fe2VX(X = Al, Ga)

2015 ◽  
Vol 29 (31) ◽  
pp. 1550229 ◽  
Author(s):  
M. Khalfa ◽  
H. Khachai ◽  
F. Chiker ◽  
N. Baki ◽  
K. Bougherara ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Local Density ◽  
Theoretical Data ◽  
Debye Model ◽  
Full Potential ◽  
Generalized Gradient ◽  
Augmented Plane Wave ◽  
Lattice Constants ◽  
Full Heusler ◽  
Good Agreement

The electronic structure, mechanical and thermodynamic properties of Fe2VX, (with X = Al and Ga), have been studied self consistently by employing state-of-the-art full-potential linearized approach of augmented plane wave plus local orbitals (FP-LAPW + lo) method. The exchange-correlation potential is treated with the local density and generalized gradient approximations (LDA and GGA). Our predicted ground state properties such as lattice constants, bulk modulus and elastic constants appear more accurate when we employed the GGA rather than the LDA, and these results are in very good agreement with the available experimental and theoretical data. Further, thermodynamic properties of Fe2VAl and Fe2VGa are predicted with pressure and temperature in the ranges of 0–40 GPa and 0–1500 K using the quasi-harmonic Debye model. We have obtained successfully the variations of the heat capacities, primitive cell volume and volume expansion coefficient.

scholarly journals Shannon, R\’enyi, Tsallis entropies of 1s$^2$-State Atomic System

2021 ◽  
Author(s):  
Hamid Al-Jibbouri
Keyword(s):  
Electron Density ◽  
Atomic Number ◽  
Atomic System ◽  
Research Topic ◽  
Hartree Fock ◽  
The Core ◽  
Isoelectronic Series ◽  
The Difference ◽  
Helium Isoelectronic Series ◽  
Good Agreement

The Shannon, R\’enyi, and Tsallis entropies of normalized electron density in position and momentum spaces are studied for the 1s${}^{2}$ state of Helium-isoelectronic series. Within single-zeta $\beta$-type orbitals ($\beta$TOs), the Hartree-Fock-Roothaan (HFR) calculations are considered and condensed on the most features of the physical results. The information quantities with atomic number deal with the interactions between the core and valence regions of the atom and thus enhance a geometrical understanding for the difference. It is assumed that the presented result might be a significant reference for further research topic on theoretical information quantities of atomic and molecular. Indeed, Our results have a good agreement in comparison with the previous published results.

The structural, electronic, elastic and thermodynamic properties of V2AX (A = B, Al, Ga, In and TI; X = C and N): A DFT calculation

2019 ◽  
Vol 33 (30) ◽  
pp. 1950359
Author(s):  
Chunying Zuo ◽  
Baishu Chen ◽  
Cheng Zhong ◽  
Jianhua Zhao
Keyword(s):  
Thermodynamic Properties ◽  
Shear Modulus ◽  
Mechanical Stability ◽  
Phonon Dispersion ◽  
Shape Change ◽  
Theoretical Data ◽  
Total Density ◽  
Barrier Coating ◽  
Machinability Index ◽  
Experimental Values

The structural, electronic, elastic and thermodynamic properties of [Formula: see text] ([Formula: see text], Al, Ga, In and TI; [Formula: see text] and N) phase have been systematically investigated by the first principles. The optimized lattice parameters are in good agreement with the experimental values and better than the available theoretical data. We calculated the elastic constants [Formula: see text] and the total density of states, which verified mechanical stability and electronic structural stability, respectively. The other elastic parameters including bulk modulus, shear modulus, Young’s modulus, Cauchy pressure, shear anisotropy factor, linear compressibility coefficients, Pugh’s ratio, Poissons’s ratio, microhardness parameter and machinability index are calculated and discussed in this work. The results show that the compounds we studied are stable in mechanics and are anisotropic materials; the compressibility along [Formula: see text]-axis is lower than that along [Formula: see text]-direction except for [Formula: see text] ([Formula: see text] and N); the compounds of [Formula: see text] ([Formula: see text]) and [Formula: see text] ([Formula: see text]) are brittle in nature, and [Formula: see text] and V2TIN are ductile in nature; the shear modulus [Formula: see text] limits the mechanical stability of the materials under consideration; the ability to resist shape change and the stiffness of [Formula: see text] are stronger compared with [Formula: see text] when A takes B, Al, Ga, In, TI, respectively. Finally we have estimated the Vickers hardness which shows that the hardness of the [Formula: see text] ([Formula: see text], Al, Ga, In, TI) would decrease when C is replaced by N. At last, we investigated the thermodynamic properties of [Formula: see text] by calculating the phonon dispersion, Debye temperature and minimum thermal conductivity. The results show that all structures are dynamical stable and the compounds of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] are candidates for thermal barrier coating (TBC) materials.

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