Structural, Thermodynamic, Elastic, and Electronic Properties of α-SnS at High Pressure from First-Principles Investigations

2015 ◽  
Vol 70 (11) ◽  
pp. 949-960 ◽  
Author(s):  
Chun Mei Liu ◽  
Chao Xu ◽  
Man Yi Duan
Keyword(s):  
Experimental Data ◽  
Electronic Properties ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Energy Relation ◽  
Potential Density ◽  
Functional Theory ◽  
Free Energy Relation ◽  
Similar Growth ◽  
Pseudo Potential

AbstractSnS has potential technical applications, but many of its properties are still not well studied. In this work, the structural, thermodynamic, elastic, and electronic properties of α-SnS have been investigated by the plane wave pseudo-potential density functional theory with the framework of generalised gradient approximation. The calculated pressure-dependent lattice parameters agree well with the available experimental data. Our thermodynamic properties of α-SnS, including heat capacity CP , entropy S, and Gibbs free energy relation of –(GT –H0) curves, show similar growth trends as the experimental data. At T=298.15 K, our CP =52.31 J/mol·K, S=78.93 J/mol·K, and –(GT –H0)=12.03 J/mol all agree very well with experimental data CP =48.77 J/mol·K and 49.25 J/mol·K, S=76.78 J/mol·K, and –(GT –H0)=12.38 J/mol. The elastic constants, together with other elastic properties, are also computed. The anisotropy analyses indicate obvious elastic anisotropy for α-SnS along different symmetry planes and axes. Moreover, calculations demonstrate that α-SnS is an indirect gap semiconductor, and it transforms to semimetal with pressure increasing up to 10.2 GPa. Combined with the density of states, the characters of the band structure have been analysed in detail.

Investigations of the Optical Properties of LaNi5 and LaNi4.5Sn0.5

2013 ◽  
Vol 321-324 ◽  
pp. 495-498 ◽  
Author(s):  
Dong Chen ◽  
Chao Xu
Keyword(s):  
Experimental Data ◽  
Refractive Index ◽  
Optical Properties ◽  
Density Functional ◽  
Low Frequency ◽  
Potential Method ◽  
Frequency Region ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Pseudo Potential

The reflectivity, loss function, refractive index, extinction coefficient and dielectric function of the LaNi5and LaNi4.5Sn0.5intermetallic compounds are investigated through the plane-wave pseudo-potential method based on the density functional theory. The effects of Sn impurity are discussed and some interesting features are found in the low frequency region. Some important optical properties such as static dielectric constant and static refractive index are obtained. The equation [n (0)]2=ε1(0)is satisfied according to our calculation, which indicates that our results are correct and reasonable. Nevertheless, the calculated results need to be testified in the future due to the lack of experimental data.

Structural Stability and Chemical Bonding of TiN: Ab Initio Study

2014 ◽  
Vol 1047 ◽  
pp. 41-44
Author(s):  
Mamta Chauhan ◽  
Dinesh Chandra Gupta ◽  
Idris Hamid Bhat
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
High Pressure ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
B2 Phase ◽  
Pseudo Potential ◽  
Electronic Behavior

We have performed ab-initio calculations to investigate the structural and electronic behavior of TiN in the stable B1 and high pressure B2 phases using pseudo-potential plane wave approach within the framework of density functional theory. The calculated results show agreement with the experimental data. The present electronic behavior, determined by total energy calculations with generalized gradient approximation for exchange and correlation interactions, is observed to be similar in both B1 and B2 phases showing metallic, covalent as well as ionic bonding of TiN. The investigations in B2 phase need validation experimentally as well as theoretically.

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.

Pressure effect on the mechanical and electronic properties of orthorhombic-C20

2018 ◽  
Vol 32 (31) ◽  
pp. 1850380 ◽  
Author(s):  
Jian-Li Ma ◽  
Zhi-Fen Fu ◽  
Qun Wei ◽  
Peng Liu ◽  
Jian-Ping Zhou
Keyword(s):  
High Pressure ◽  
Electronic Properties ◽  
Debye Temperature ◽  
Density Functional ◽  
Superhard Material ◽  
Elastic Anisotropy ◽  
Systematic Investigation ◽  
Functional Theory ◽  
Temperature Changes ◽  
The Density Functional Theory

A systematic investigation of structural, mechanical, elastic anisotropy and electronic properties of a recently reported novel superhard material orthorhombic [Formula: see text] ([Formula: see text]-[Formula: see text]) under pressure is performed utilizing the density functional theory in this work. The crystal structure parameters are obtained at zero as well as at high pressure. Pressure induced elastic constants [Formula: see text], polycrystalline aggregate elastic modulus [Formula: see text], [Formula: see text] ratio, and Debye temperature changes for [Formula: see text]-[Formula: see text] have been determined. The crystal elastic anisotropies of the ultra-incompressible [Formula: see text]-[Formula: see text] are investigated in the pressure range of 0–100 GPa. The Lyakhov–Oganov model is applied to predict the hardness as functions of pressure. The calculated results reveal that [Formula: see text]-[Formula: see text] possesses high elastic anisotropy under zero pressure and high pressure, and the hardness of [Formula: see text]-[Formula: see text] decreases with pressure, while the Debye temperature behaves with the opposite trend. The results of electronic structure indicate that [Formula: see text]-[Formula: see text] exhibits insulator characteristics, and the band gap increases with pressure. This work is expected to provide a useful guide for the future synthesis and application of [Formula: see text]-[Formula: see text].

First-principles investigation of the elastic and thermodynamic properties of ReC2 (Re = Ho, Nd, Pr)

2015 ◽  
Vol 29 (01) ◽  
pp. 1450256 ◽  
Author(s):  
Wen Huang ◽  
Haichuan Chen
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Lattice Constants ◽  
Generalized Gradient Approximation ◽  
Temperature Melting

The elastic and thermodynamic properties of Re C 2 (Re = Ho , Nd , Pr ) have been investigated by using the first-principles density functional theory within the generalized gradient approximation. The computed lattice constants of Re C 2 are in agreement with the experimental data. The calculated elastic constants reveal that all compounds are mechanically stable. The shear modulus, Young's modulus, Poisson's ratio σ, the ratio B/G, shear anisotropy and elastic anisotropy are also calculated. Finally, the Vicker hardness, Debye temperature, melting point and thermal conductivity have been predicted.

Ab initio investigation of the structural and electronic properties of the MgFBrxCl1-x quaternary alloy

2014 ◽  
Vol 28 (29) ◽  
pp. 1450228
Author(s):  
Ali Mokhtari ◽  
Mohammad Alidoosti
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Quaternary Alloy ◽  
Nonlinear Dependence ◽  
Partial Density ◽  
Quaternary Alloys ◽  
Functional Theory ◽  
Lattice Constants ◽  
Structural And Electronic Properties ◽  
Pseudo Potential

In the present work, we have performed first principles calculations to study the structural and electronic properties of the MgFBr x Cl 1-x quaternary alloys using the pseudo-potential plane wave approach within the framework of density functional theory. By using the optimized initial parameters, we have obtained the physical quantities such as equilibrium lattice constants a and c, cohesive energy and band gap and then fitted the results by a quadratic expression for all x compositions. The results of bulk modulus exhibit nearly linear concentration dependence (LCD) but other quantities show nonlinear dependence. Finally, we have calculated the total and angular momentum decomposed (partial) density of states and determined the contributions of different orbitals of each atoms.

External Chemical Reactivity of Fullerenes and Nanotubes

2001 ◽  
Vol 675 ◽  
Author(s):  
Seongjun Park ◽  
Deepak Srivastava ◽  
Kyeongjae Cho
Keyword(s):  
Density Functional ◽  
Chemical Reactivity ◽  
Density Functional Theory Calculations ◽  
Reaction Energy ◽  
Potential Density ◽  
Functional Theory ◽  
Ab Initio Simulation ◽  
Total Reaction ◽  
Local Bonding ◽  
Pseudo Potential

ABSTRACTThe external chemical reactivity of graphene sheet, fullerenes and carbon nanotubes has been investigated. The total reaction energy is analyzed with several contributing terms and formulated as a function of the pyramidal angles of C atoms. We have determined the parameters for the formulae from ab initio simulation of graphene. We have applied them to predict hydrogenation energy of several nanotubes and C60, and demonstrated that the predicted total reaction energies are very close to the results of total energy pseudo-potential density functional theory calculations. This analysis can be used to predict the reaction energy and local bonding configuration of a reactant with diverse fullerenes and nanotubes within 0.1 eV accuracy.

First-Principles Study on the Elastic and Electronic Properties of 2H-CuGaO2

2013 ◽  
Vol 446-447 ◽  
pp. 3-7 ◽  
Author(s):  
Wen Ting Liu ◽  
Zheng Tang Liu
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Anisotropy Ratio ◽  
Functional Theory ◽  
Indirect Band Gap ◽  
Calculated Equilibrium ◽  
Elastic Coefficients ◽  
Good Agreement

The structure, elastic and electronic properties of 2H-CuGaO2are calculated using the plane-wave ultrasoft pseudopotential technique based on the first-principles density functional theory. The calculated equilibrium lattice parameters is in good agreement with experimental and reported values. The elastic coefficients, bulk, shear and Youngs modulus, Poissons ratio and elastic anisotropy ratio of 2H-CuGaO2were calculated. The electronic properties of 2H-CuGaO2have been calculated and the results show that 2H-CuGaO2has an indirect band gap.

CHARGE TRANSFER AND DIELECTRIC PROPERTIES OF TiO2–GRAPHENE COMPOSITES

2012 ◽  
Vol 02 (01) ◽  
pp. 1250004
Author(s):  
CAI-HUA ZHOU ◽  
QIAN XU ◽  
SHENG-TAO LI ◽  
XIANG ZHAO
Keyword(s):  
Charge Transfer ◽  
Dielectric Properties ◽  
Density Functional ◽  
Dielectric Constants ◽  
Potential Density ◽  
Functional Theory ◽  
Transfer Properties ◽  
Pseudo Potential ◽  
Interfacial Charge ◽  
Atomic Type

The electronic structures and dielectric properties of TiO2 –graphene composites are studied using pseudo-potential density functional theory. It is shown that interfacial charge transfer properties of graphene/ TiO2 are influenced by the atomic type on TiO2 surface. The interfacial interaction of graphene with Ti -terminated surface is so strong that it causes a buckling structural graphene, and the titanium atomic d electrons are transferred obviously from TiO2 to graphene. It is revealed that dielectric properties of the composites are greatly affected by both band structures and electronic transitions. Compared with bulk TiO2 , dielectric constants of TiO2 –graphene composites are significantly improved.

High-Pressure Electronic and Optical Properties of α-Si3N4

2011 ◽  
Vol 415-417 ◽  
pp. 2288-2291
Author(s):  
Chang Chun Chen ◽  
Xiao Ju Geng ◽  
Ying Bin Li ◽  
Ben Hai Yu ◽  
Dong Chen
Keyword(s):  
Experimental Data ◽  
Dielectric Function ◽  
Density Functional ◽  
Potential Method ◽  
Band Structure Calculation ◽  
Functional Theory ◽  
Lattice Constants ◽  
The Density Functional Theory ◽  
The Stability ◽  
Pseudo Potential

Based on the density functional theory, the plane-wave pseudo-potential method is performed to investigate the structural properties of α-Si3N4. The ground-state lattice parameters (i.e. lattice constants and cell volume) agree quite well with the experimental data. From the band structure calculation, we found that the stability of α-Si3N4is due mainly to the interaction among the Si-s, Si-p and N-p states. The imaginary part of the dielectric function has a sharp peak at 8.2eV. For the real part of the dielectric function, the highest peak locates at 6.5eV. Our calculated results are in good agreement with the experimental data and previous theoretical values. Therefore, the calculated results may provide useful information for further investigations of α-Si3N4.

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