scholarly journals Ab initio Study of the Structure, Elastic, and Electronic Properties of Ti3(Al1-nSin)C2 Layered Ternary Compounds

2020 ◽  
Author(s):  
S. Ahams ◽  
A. Shaari ◽  
Rashid Ahmed ◽  
N. Abdul Pattah ◽  
M. Idris ◽  
...  
Keyword(s):  
Ab Initio ◽  
Density Of States ◽  
Mechanical Stability ◽  
Electrical Contact ◽  
Ceramic Materials ◽  
Systematic Investigation ◽  
Max Phase ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Pseudopotential Approach

Abstract The MAX phase materials such as layered ternary carbides that simultaneously exhibit characteristics of metallic and ceramic materials have received substantial interest in recent years. Here, we present a systematic investigation of the electronic, structural stabilities, and elastic properties of Ti3(Al1-nSin)C2 (n = 0,1) MAX phase materials using the ab initio method via a plane-wave pseudopotential approach within generalized-gradient-approximations. The computed electronic band structures and projected density of states show that both Ti3SiC2 and Ti3AlC2 are metallic materials with a high density of states at the Fermi level emanating mainly from Ti-3d. Using the calculated elastic constants, the mechanical stability of the compounds was confirmed following the Born stability criteria for hexagonal structures. The Cauchy pressure and the Pugh’s ratio values establish the brittle nature of the Ti3SiC2 and Ti3AlC2 MAX phase materials. Due to their intriguing physical properties, these materials are expected to be suitable for applications such as thermal shock refractories and electrical contact coatings.

scholarly journals Ab initio study of the structure, elastic, and electronic properties of Ti3(Al1−nSin)C2 layered ternary compounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. T. Ahams ◽  
A. Shaari ◽  
R. Ahmed ◽  
N. F. Abdul Pattah ◽  
M. C. Idris ◽  
...  
Keyword(s):  
Ab Initio ◽  
Density Of States ◽  
Mechanical Stability ◽  
Electrical Contact ◽  
Ceramic Materials ◽  
Systematic Investigation ◽  
Max Phase ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Pseudopotential Approach

AbstractThe MAX phase materials such as layered ternary carbides that simultaneously exhibit characteristics of metallic and ceramic materials have received substantial interest in recent years. Here, we present a systematic investigation of the electronic, structural stabilities, and elastic properties of Ti3(Al1−nSin)C2 (n = 0,1) MAX phase materials using the ab initio method via a plane-wave pseudopotential approach within generalized-gradient-approximations. The computed electronic band structures and projected density of states show that both Ti3SiC2 and Ti3AlC2 are metallic materials with a high density of states at the Fermi level emanating mainly from Ti-3d. Using the calculated elastic constants, the mechanical stability of the compounds was confirmed following the Born stability criteria for hexagonal structures. The Cauchy pressure and the Pugh’s ratio values establish the brittle nature of the Ti3SiC2 and Ti3AlC2 MAX phase materials. Due to their intriguing physical properties, these materials are expected to be suitable for applications such as thermal shock refractories and electrical contact coatings.

scholarly journals New MAX Phase Compound Mo2TiAlC2: First-principles Study

2016 ◽  
Vol 8 (2) ◽  
pp. 109-117 ◽  
Author(s):  
M. S. Ali ◽  
M. A. Rayhan ◽  
M. A. Ali ◽  
R. Parvin ◽  
A. K. M. A. Islam
Keyword(s):  
Optical Properties ◽  
Density Of States ◽  
First Principles ◽  
Mechanical Stability ◽  
Young Modulus ◽  
Max Phase ◽  
Generalized Gradient ◽  
Max Phases ◽  
Anisotropic Factor ◽  
Phase Compound

A theoretical study of the Mo2TiAlC2 compound belonging to the MAX phases has been performed by using the first-principles pseudopotential plane-wave method within the generalized gradient approximation (GGA). We have calculated the structural, elastic, electronic and optical properties of Mo2TiAlC2. To confirm mechanical stability, the elastic constants Cij are calculated. Other elastic parameters such as bulk modulus, shear modulus, compressibility, Young modulus, anisotropic factor, Pugh ratio, Poisson’s ratio are also calculated. The energy band structure and density of states are calculated and analyzed. The results show that the electrical conductivity is metallic with a high density of states at the Fermi level in which Mo 4d states dominate. Furthermore, the optical properties such as dielectric function, refractive index, photoconductivity, absorption coefficients, loss function and reflectivity are also calculated. Its reflectance spectrum shows that it has the potential to be used as a promising shielding material to avoid solar heating.

scholarly journals Physical Properties Investigations of Ternary-Layered Carbides M2PbC (M = Ti, Zr and Hf): First-Principles Calculations

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1445
Author(s):  
Tahani A. Alrebdi ◽  
Mohammed Benali Kanoun ◽  
Souraya Goumri-Said
Keyword(s):  
Elastic Constants ◽  
First Principles ◽  
Mechanical Stability ◽  
Electronic Band Structure ◽  
Max Phase ◽  
Mechanical And Thermal Properties ◽  
First Principles Calculations ◽  
Electronic Band ◽  
Bonding Properties ◽  
Structure Density

We investigated structure optimization, mechanical stability, electronic and bonding properties of the nanolaminate compounds Ti2PbC, Zr2PbC, and Hf2PbC using the first-principles calculations. These structures display nanolaminated edifices where MC layers are interleaved with Pb. The calculation of formation energies, elastic moduli and phonons reveal that all MAX phase systems are exothermic, and are intrinsically and dynamically stable at zero and under pressure. The mechanical and thermal properties are reported with fundamental insights. Results of bulk modulus and shear modulus show that the investigated compounds display a remarkable hardness. The elastic constants C11 and C33 rise more quickly with an increase in pressure than that of other elastic constants. Electronic and bonding properties are investigated through the calculation of electronic band structure, density of states, and charge densities.

scholarly journals An ab-initio Investigation: The physical properties of ScIr-=SUB=-2-=/SUB=- Superconductor -=SUP=-*-=/SUP=-

2019 ◽  
Vol 61 (4) ◽  
pp. 659
Author(s):  
Uttam Kumar Chowdhury ◽  
Tapas Chandra Saha
Keyword(s):  
Physical Properties ◽  
Ab Initio ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Structural Parameters ◽  
Ultraviolet Region ◽  
Electronic Band ◽  
Cauchy Pressure ◽  
Pseudopotential Approach ◽  
First Time

AbstractUsing ab initio technique the physical properties of ScIr_2 superconductor have been investigated with T _c 1.03 K with a MgCu_2-type structure. We have carried out the plane-wave pseudopotential approach within the framework of the first-principles density functional theory (DFT) implemented within the CASTEP code. The calculated structural parameters confirm a good agreement with the experimental and other theoretical results. Using the Voigt-Reuss-Hill (VRH) averaging scheme the most important elastic properties including the bulk modulus B, shear modulus G , Young’s modulus E and Poisson’s ratio ν of ScIr_2 are determined. At ambient condition, the values of Cauchy pressure and Pugh’s ratio exhibit ductile nature of ScIr_2. The electronic and optical properties of ScIr_2 were investigated for the first time. The electronic band structure reveals metallic conductivity and the major contribution comes from Ir-5 d states. In the ultraviolet region the reflectivity is high up to 50 eV as evident from the reflectivity spectrum.

scholarly journals A First-Principles Study of Structure, Elastic and Electronic Properties of GeTiO3 as Environmentally Innocuous Ferroelectric Perovskites

2021 ◽  
Vol 66 (6) ◽  
pp. 539
Author(s):  
G.K. Shiferaw ◽  
M.W. Menberu
Keyword(s):  
Elastic Constant ◽  
Density Of States ◽  
Spontaneous Polarization ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Structural Parameters ◽  
Theoretical Data ◽  
Lattice Parameter ◽  
Generalized Gradient ◽  
Electronic Band

The structural parameters, elastic properties, spontaneous polarization, electronic band structure, and density of states (DOS) of GeTiO3 in tetragonal phase have been studied computationally using pseudopotential plane-wave (PP-PW) method based on the density functional theory (DFT). The generalized gradient approximation (GGA) was used to estimate the exchange-correlation energies. The equilibrium lattice parameter, unit cell volume, bulk modulus and its derivative are obtained and compared with the available theoretical data. The elastic characteristics such as elastic constants, Poisson’s ratio, elastic modulus, and anisotropy factor are obtained in the pressure range 0–50 GPa. Our computed results of elastic constant satisfy Born’s stability criterion. In view of Pugh’s prediction standard, the material is taken as ductile. Once the elastic constant is calculated, the Debye temperature of GeTiO3 compound is also evaluated from the average sound velocity. The density of states, band structures, and charge-density distribution are discussed and compared with previous computational results. The calculation within Berry’s phase approach indicate a high spontaneous polarization of tetragonal GeTiO3 (1.125 C/m2). Thus, the substance is identifi ed as a promising environmentally friendly ferroelectric material.

Physical properties of ternary silicide superconductors Li2XSi3 (X = Rh, Os): An ab initio study

2017 ◽  
Vol 31 (20) ◽  
pp. 1750135 ◽  
Author(s):  
M. A. Alam ◽  
M. A. K. Zilani ◽  
F. Parvin ◽  
M. A. Hadi
Keyword(s):  
Physical Properties ◽  
Ab Initio ◽  
Ab Initio Method ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Generalized Gradient Approximation ◽  
Bonding Properties ◽  
First Time ◽  
Electronic Band Structures ◽  
Ternary Silicide

An ab initio method, based on the plane wave pseudopotential and the generalized gradient approximation (GGA), is performed to investigate the physical properties such as structural, elastic, electronic and bonding properties of newly synthesized Li2RhSi3 and predicted Li2OsSi3 ternary silicide superconductors for the first time. Both of these compounds are mechanically stable and are brittle in nature. They also have good machinability. Electronic band structures reveal that these compounds have metallic characteristics. They possess complex bonding nature (metallic, covalent and ionic). According to theoretical Vickers hardness, Li2RhSi3 is softer than Li2OsSi3.

scholarly journals The structural, elastic and optical properties of ScM (M = Rh, Cu, Ag, Hg) intermetallic compounds under pressure by ab initio simulations

2016 ◽  
Vol 05 (04) ◽  
pp. 1650024 ◽  
Author(s):  
Md. Lokman Ali ◽  
Md. Zahidur Rahaman ◽  
Md. Atikur Rahman
Keyword(s):  
Optical Properties ◽  
Ab Initio ◽  
Elastic Constants ◽  
Energy Region ◽  
Density Functional ◽  
Mechanical Stability ◽  
Computer Code ◽  
High Energy ◽  
High Energy Region ◽  
Generalized Gradient

The influence of pressure on the structural and elastic properties of ScM ([Formula: see text], Cu, Ag, Hg) compounds has been investigated by using ab initio approach pseudopotential plane-wave method based on the density functional theory within the generalized gradient approximation (GGA). The optical properties have been investigated under zero pressure. It is found that the optimized lattice parameters for all metals are in good agreement with the experimental data and other available theoretical values. We obtained three independent elastic constants [Formula: see text] ([Formula: see text] and [Formula: see text]) and various elastic parameters such as bulk modulus [Formula: see text], shear modulus [Formula: see text], Young’s modulus [Formula: see text], Poisson’s ratio [Formula: see text] and anisotropy factor [Formula: see text] as a function of pressure. In addition, the mechanical stability and ductile/brittle nature are also investigated from the calculated elastic constants. The study of optical properties reveals that all of these compounds possess good absorption coefficient in the high energy region and the refractive index of all these compounds is higher in the low energy region and gradually decreased in the high energy region. All these calculations have been carried out using the CASTEP computer code.

scholarly journals Electronic and Optical Properties of Mg2GeO4 Under Pressure Effect: ab Initio Study

2021 ◽  
Author(s):  
Yunxia Zhang ◽  
Li’na Xiao
Keyword(s):  
Optical Properties ◽  
Density Of States ◽  
Pressure Dependence ◽  
Mechanical Stability ◽  
Electronic Band Structure ◽  
Structural Parameters ◽  
Partial Density ◽  
Band Structures ◽  
Electronic Band ◽  
Electronic And Optical Properties

Abstract We report first-principles studies the structural, elastic, electronic, and optical properties of Mg2GeO4 in orthorhombic structure, including pressure dependence of structural parameters, band structures, density of states, and optical constants up to 20 GPa. The calculated structural parameters are in good agreement with the available experimental values at zero pressure. The mechanical stability of Mg2GeO4 has been confirmed by calculation of the elastic constants. And the non-uniform pressure dependence of the lattice parameters may also mean that Mg2GeO4 undergoes anisotropic compression. Meanwhile, the pressure dependence of the electronic band structure, density of states and partial density of states of Mg2GeO4 up to 20 GPa were presented. The band structures show a direct band gap for this compound and the calculated band gaps expend with increasing pressure. Moreover, the evolution of the dielectric function, absorption coefficient (α(ω)), reflectivity (R(ω)), and the real part of the refractive index (n(ω)) at high pressure are also presented. According to our work, we found that the optical properties of Mg2GeO4 undergo a blue shift with increasing pressure.

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