First-Principles Study on Elastic Properties of AlN

2013 ◽  
Vol 821-822 ◽  
pp. 841-844 ◽  
Author(s):  
Xin Tan ◽  
Zhen Yang Xin ◽  
Xue Jie Liu ◽  
Qing Ge Mu
Keyword(s):  
Elastic Properties ◽  
Brittle Material ◽  
First Principles ◽  
Elastic Anisotropy ◽  
Three Dimensional ◽  
Elastic Stiffness ◽  
Wurtzite Structure ◽  
Shear Moduli ◽  
Young’S Moduli ◽  
Zinc Blende

Structural and elastic properties of AlN are investigated by using First-principles. Both of wurtzite and zinc-blende structures are investigated, respectively. The bulk moduli of the wurtzite structure and zinc blende AlN are 194.2GPa and 187GPa, which obtained by the elastic stiffness constants respectively. Shear moduli are 136GPa and 124GPa. Young's moduli are 331GPa and 305GPa. Poisson's ratio and Pugh criterion suggests that both of them are brittle material. The brittleness of wurtzite AlN is higher than that of zinc-blende AlN. The elastic anisotropy of the bulk moduli and shear moduli were discussed. Three-dimensional anisotropic of the young's modulus were analyzed.

First-principles study on the structural, elastic and electronic properties of the four Si3Sb4 compounds

2019 ◽  
Vol 33 (05) ◽  
pp. 1950047
Author(s):  
Ruike Yang ◽  
Bao Chai ◽  
Qun Wei ◽  
Minhua Xue ◽  
Ye Zhou
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Elastic Anisotropy ◽  
Functional Theory ◽  
Shear Moduli ◽  
Young’S Moduli ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

For novel [Formula: see text]-Si3Sb4, pseudocubic-Si3Sb4, cubic-Si3Sb4 and [Formula: see text]-Si3Sb4, the structural, elastic and electronic properties are investigated using first-principles density functional theory (DFT). The elastic constants and phonon dispersion spectra show that they are mechanically and dynamically stable. The bulk moduli, shear moduli, Young’s moduli, Poisson’s ratios and Pugh ratios for the four compounds have been calculated. The bulk moduli indicate that the bond strength of [Formula: see text]-Si3Sb4 is stronger than others. The values of the Poisson’s ratios and Pugh ratios show that pseudocubic-Si3Sb4 is the stiffest among the four Si3Sb4 compounds. Tetragonal Si3Sb4 are more brittle than cubic Si3Sb4. For the four Si3Sb4 compounds, the elastic anisotropies are analyzed via the anisotropic indexes and the 3D surface constructions. The [Formula: see text]-Si3Sb4 elastic anisotropy is stronger than others and the [Formula: see text]-Si3Sb4 is weaker than others. The calculated band structures show that they exhibit metallic features. The results of their TDOS show that there are many similarities. The peaks of TDOS are derived from the contributions of Si “s”, Si “p”, Sb “s” and Sb “p” states.

Structural and elastic properties of Cu6Sn5 and Cu3Snfrom first-principles calculations

2009 ◽  
Vol 24 (7) ◽  
pp. 2361-2372 ◽  
Author(s):  
Jiunn Chen ◽  
Yi-Shao Lai ◽  
Ping-Feng Yang ◽  
Chung-Yuan Ren ◽  
Di-Jing Huang
Keyword(s):  
Electronic Structure ◽  
Elastic Modulus ◽  
Elastic Properties ◽  
First Principles ◽  
Elastic Anisotropy ◽  
Lattice Structure ◽  
Elastic Stiffness ◽  
First Principles Calculations ◽  
Atomic Lattice ◽  
Microstructure Effect

We investigated the elastic properties of two tin-copper crystalline phases, the η′-Cu6Sn5 and ε-Cu3Sn, which are often encountered in microelectronic packaging applications. The full elastic stiffness of both phases is determined based on strain-energy relations using first-principles calculations. The computed results show the elastic anisotropy of both phases that cannot be resolved from experiments. Our results, suggesting both phases have the greatest stiffness along the c direction, particularly showed the unique in-plane elastic anisotropy associated with the lattice modulation of the Cu3Sn superstructure. The polycrystalline moduli obtained using the Voigt-Reuss scheme are 125.98 GPa for Cu6Sn5 and 134.16 GPa for Cu3Sn. Our data analysis indicates that the smaller elastic moduli of Cu6Sn5 are attributed to the direct Sn–Sn bond in Cu6Sn5. We reassert the elastic modulus and hardness of both phases using the nanoindentation experiment for our calculation benchmark. Interestingly, the computed polycrystalline elastic modulus of Cu6Sn5 seems to be overestimated, whereas that of Cu3Sn falls nicely in the range of reported data. Based on the observations, the elastic modulus of Cu6Sn5 obtained from nanoindentation tests admit the microstructure effect that is absent for Cu3Sn is concluded. Our analysis of electronic structure shows that the intrinsic hardness and elastic modulus of both phases are dominated by electronic structure and atomic lattice structure, respectively.

High pressure behaviour and elastic properties of a dense inorganic–organic framework

2016 ◽  
Vol 45 (10) ◽  
pp. 4303-4308 ◽  
Author(s):  
Guoqiang Feng ◽  
Xingxing Jiang ◽  
Wenjuan Wei ◽  
Pifu Gong ◽  
Lei Kang ◽  
...  
Keyword(s):  
High Pressure ◽  
Elastic Properties ◽  
Powder Diffraction ◽  
First Principles ◽  
First Principles Calculations ◽  
Shear Moduli ◽  
X Ray ◽  
Young’S Moduli ◽  
Poisson's Ratios ◽  
Organic Framework

The hydrostatic behaviour of a cubic dense inorganic–organic framework [DABCOH22+][K(ClO4)3] has been systematically studied via high-pressure synchrotron X-ray powder diffraction. Further first principles calculations of full elastic tensors give full mapping of the Young's moduli, shear moduli and Poisson's ratios of this material.

scholarly journals Anisotropic elastic properties of FexB (x = 1, 2, 3) under pressure. First-principles study

2016 ◽  
Vol 34 (3) ◽  
pp. 503-516 ◽  
Author(s):  
A. Gueddouh ◽  
B. Bentria ◽  
Y. Bourourou ◽  
S. Maabed
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Poisson Ratio ◽  
Pressure Effects ◽  
Mechanical Anisotropy ◽  
First Principles Calculation ◽  
Young’S Moduli ◽  
Anisotropic Elastic

AbstractSpin-polarization (SP) and pressure effects have been used to better clarify and understand anisotropic elastic properties of Fe-B intermetallic compounds using the first-principles calculation with generalized gradient approximation (GGA) within the plane-wave pseudopotential density functional theory. Elastic properties, including bulk, shear and Young’s moduli as well as Poisson ratio were obtained by Voigt-Reuss-Hill approximation. All studied Fe-B compounds were mechanically stable. The brittle and ductile properties were discussed using bulk to shear moduli ratio (B/G) of the studied structures in the pressure range of 0 GPa to 90 GPa in order to predict the critical pressure of phase transition from ferromagnetic (FM) to nonmagnetic (NM) state. Mechanical anisotropy in both cases was discussed by calculating different anisotropic indexes and factors. We have plotted three-dimensional (3D) surfaces and planar contours of the bulk and Young’s moduli of FexB (x = 1, 2, 3) compounds for some crystallographic planes, (1 0 0), (0 1 0) and (0 0 1), to reveal their elastic anisotropy. On the basis of anisotropic elastic properties the easy and hard axes of magnetization for the three studied compounds were predicted.

Structural, Electronic and Elastic Properties of Neptunium Bismuthide (NpBi)

2016 ◽  
Vol 1141 ◽  
pp. 180-183
Author(s):  
Chandrabhan Makode ◽  
Mahendra Aynyas ◽  
Jagdeesh Pataiya ◽  
Archana Singh ◽  
Sankar P. Sanyal
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Shear Moduli ◽  
Young’S Moduli ◽  
Theoretical Results ◽  
Good Agreement

The electronic, elastic and mechanical properties of neptunium bismuthide have been studied systematically using first principles density functional theory within generalized gradient approximation. Ground state properties such as lattice constant (a0), bulk modulus (B), its pressure derivative (B′) and elastic constants are calculated. The present results are in good agreement with the experimental and other available theoretical results. Poisson’s ratio (σ), Young’s moduli (E), shear moduli (GH) and the ratio of elastic anisotropy factor (A) are also estimated.

First-principles study of electronic structure, chemical bonding and elastic properties for new superconductor CaFeAs2

2017 ◽  
Vol 31 (02) ◽  
pp. 1650263
Author(s):  
J. G. Yan ◽  
Z. J. Chen ◽  
G. B. Xu ◽  
Z. Kuang ◽  
T. H. Chen ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Elastic Properties ◽  
Density Of States ◽  
First Principles ◽  
Elastic Anisotropy ◽  
First Principles Calculation ◽  
Hard Material ◽  
Dirac Cone ◽  
First Time ◽  
New Superconductor

Using first-principles calculation we investigated the structural, electronic and elastic properties of paramagnetic CaFeAs2. Our results indicated that the density of states (DOS) was dominated predominantly by Fe-3[Formula: see text] states at Fermi levels, and stronger hybridization exists between As1 and As1 atoms. Three hole pockets are formed at [Formula: see text] and Z points, and two electronic pockets are formed at A and E points. The Dirac cone-like bands appear near B and D points. For the first time we calculated the elastic properties and found that CaFeAs2 is a mechanically stable and moderately hard material, it has elastic anisotropy and brittleness, which agrees well with the bonding picture and the calculation of Debye temperature ([Formula: see text]).

scholarly journals First-principles generated mechanical property database for multi-component Al alloys: Focusing on Al-rich corner

2017 ◽  
Vol 53 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. Wang ◽  
Y. Du ◽  
X. Tao ◽  
Y. Ouyang ◽  
L. Zhang ◽  
...  
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Linear Thermal Expansion ◽  
Elastic Stiffness ◽  
Debye Model ◽  
Al Alloys ◽  
Processing Route ◽  
Temperature Dependent ◽  
Polycrystalline Aggregates ◽  
Strain Stress

Systematic first-principles calculations of the single crystal elastic stiffness constants (cij?s) and the polycrystalline aggregates including bulk modulus (B), shear modulus (G), Young?s modulus (E) have been performed for series binary and ternary Al compounds at 0 K. In addition, the temperature-dependent elastic properties for some technologically important phases are calculated. The cij?s are calculated by means of an efficient strain-stress method. Phonon density of states or Debye model is employed to calculate the linear thermal expansion, which is then used to calculate the temperature dependence of elastic properties. The calculated temperature-dependent elastic properties are compiled in the format of CALPHAD (CALculation of PHAse Diagram) type formula. The presently computed elastic properties for Al compounds are needed for simulation of microstructure evolution of commercial Al alloys during series of processing route.

Effect of variations in microstructure on clay elastic anisotropy

Geophysics ◽  
2020 ◽  
Vol 85 (2) ◽  
pp. MR73-MR82 ◽  
Author(s):  
Colin M. Sayers ◽  
Lennert D. den Boer
Keyword(s):  
Elastic Properties ◽  
Volume Fraction ◽  
Elastic Anisotropy ◽  
Rock Physics ◽  
Elastic Stiffness ◽  
Single Domain ◽  
Model Parameters ◽  
Stiffness Tensor ◽  
Elastic Stiffness Tensor ◽  
Clay Platelets

Rock physics provides a crucial link between seismic and reservoir properties, but it requires knowledge of the elastic properties of rock components. Whereas the elastic properties of most rock components are known, the anisotropic elastic properties of clay are not. Scanning electron microscopy studies of clay in shales indicate that individual clay platelets vary in orientation but are aligned locally. We present a simple model of the elastic properties of a region (domain) of locally aligned clay platelets that accounts for the volume fraction, aspect ratio, and elastic-stiffness tensor of clay platelets, as well as the effective elastic properties of the interplatelet medium. Variations in clay anisotropy are quantified by examining the effects of varying model parameters upon the effective transverse-isotropic (TI) elastic-stiffness tensor of a domain. Statistics of these distributions and correlations between stiffnesses and anisotropy parameters enable the most probable sets of stiffnesses to be identified for rock physics calculations. The mean of these distributions is on the order of twice the mode for in-plane stiffnesses ([Formula: see text], [Formula: see text], [Formula: see text]), but it is of the same order as the mode for out-of-plane stiffnesses ([Formula: see text], [Formula: see text], [Formula: see text]). Despite random sampling, well-defined relations emerge, consistent with similar shale relations reported in the literature. Expressing these relations in terms of [Formula: see text] for a single domain of aligned clay platelets facilitates their general application. In the limit that the volume fraction approaches unity, the elastic stiffnesses thus derived reproduce those of the clay mineral assumed as platelets. Given the elastic-stiffness tensor of a single domain of aligned clay platelets, the effective TI elastic-stiffness tensor of clay is obtained by integrating over the clay-platelet orientation-distribution function.

THE FIRST-PRINCIPLES STABILITY STUDY OF PdC AND CdC COMPOUNDS

2013 ◽  
Vol 27 (06) ◽  
pp. 1350016
Author(s):  
ENGIN ATESER ◽  
HAVVA BOGAZ OZISIK ◽  
ENGIN DELIGOZ ◽  
KEMAL COLAKOGLU
Keyword(s):  
First Principles ◽  
Elastic Moduli ◽  
Stability Study ◽  
Correlation Effects ◽  
Generalized Gradient ◽  
Shear Moduli ◽  
Exchange Correlation ◽  
Zinc Blende ◽  
Debye Temperatures ◽  
Stable Structures

We have studied structural, mechanical and dynamical properties of PdC and CdC compounds to predict the most stable structure. We have focused on seven binary structure types as rock salt (RS), caesium chloride ( CsCl ), zinc blende (ZB), wurtzite (WZ), tungsten carbide (WC), cadmium telluride ( CdTe ) and nickel arsenide ( NiAs ). For modelling exchange-correlation effects we have used generalized gradient (GGA) approximation based on Perdew–Burke–Ernzhorf functional (PBE). The polycrystalline elastic moduli such as Young's and shear moduli, Poisson's ratio, sound velocities, Debye temperatures and shear anisotropic factors have been presented for mechanically stable structures using second-order elastic constants calculated from the stress-strain relations. The results show that PdC is thermodynamically, mechanically and dynamically stable in ZB structure. On the other hand, while CdC is energetically in favor of RS structure, it is mechanically and dynamically stable in ZB structure.

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