scholarly journals Modeling and simulation of mechanical and physical properties of Barium orthotitanate (Ba2TiO4) composite by Materials Studio ( MS)

2018 ◽  
Vol 22 (11) ◽  
pp. 61
Author(s):  
Najat A. Dahham1 ◽  
Abdullah Hamoud Fares2 ◽  
Khaled Abdullah Najem1
Keyword(s):  
Physical Properties ◽  
Band Gap ◽  
Mechanical Stability ◽  
Linear Method ◽  
Young Modulus ◽  
Generalized Gradient ◽  
Lame Constant ◽  
Structure Density ◽  
Indirect Band Gap ◽  
Materials Studio

This research including a study of mechanical ,physical properties (band structure, density of states)  and the elasticity constants of the Barium Ortho titanate by using Materials studio software. The calculations were based on the generalized gradient approximation  (GGA) by linear method. The calculated equilibrium lattice constants of monoclinic barium orthotitanate were: a = 0.612nm, b = 0.77nm, c = 1.05nm,calculated bulk modulus =42.3021 GPa, young modulus= 40.29 GPa, share modulus = 15.97 GPa, lame constant (λ)= 142.56 GPa ,and energy band gap=3.435eV which is indirect band gap and the composite is insulator and the electronic properties where be calculated in first Brillion zone. According the mechanical stability conditions the composite is stable mechanically. These results were calculated by Materials studio software. 

First-principles study on the band structure, magnetic and elastic properties of half-metallic Cr2MnAl

2015 ◽  
Vol 29 (24) ◽  
pp. 1550139 ◽  
Author(s):  
Santao Qi ◽  
Chuan-Hui Zhang ◽  
Bao Chen ◽  
Jiang Shen
Keyword(s):  
Band Structure ◽  
Band Gap ◽  
Elastic Properties ◽  
Density Functional ◽  
Stable State ◽  
Generalized Gradient ◽  
Half Metallic ◽  
Text Type ◽  
Calculation Results ◽  
Indirect Band Gap

In this study, we have investigated the structural, electronic, magnetic and elastic properties of the full-Heusler [Formula: see text] alloy in the framework of density functional theory with generalized gradient approximation (GGA). The calculated results showed that [Formula: see text] was stable in ferrimagnetic configuration and crystallized in the [Formula: see text]-type structure. From the band structure and density of states calculation results, we concluded that [Formula: see text] belongs to a kind of half-metallic compound with an indirect band gap of 0.37 eV. Immediately thereafter, we have analyzed the origin of half-metallic band gap. The total magnetic moment of [Formula: see text] at the stable state is [Formula: see text] per formula unit, obeying the Slater–Pauling rule [Formula: see text]. In addition, various mechanical properties have been obtained and discussed based on the three principle elastic tensor elements [Formula: see text] and [Formula: see text] for the first time in the present work. We expect that our calculated results may trigger the application of [Formula: see text] in future spintronics field.

The Electronic and Structural Properties of 3C-SiC: A First-Principles Study

2014 ◽  
Vol 971-973 ◽  
pp. 208-212 ◽  
Author(s):  
Ying Gao ◽  
Fu Chun Zhang ◽  
Wei Hu Zhang
Keyword(s):  
Band Gap ◽  
Valence Band ◽  
Conduction Band ◽  
First Principles ◽  
Density Functional ◽  
Energy Splitting ◽  
Functional Theory ◽  
Structure Density ◽  
Indirect Band Gap ◽  
Electronic And Structural Properties

We investigate geometric structure, electronic structure and ground properties of 3C-SiC as obtained form first-principles calculations based on density functional theory with the LDA, GGA, B3LYP and HSE06 method. After comparative analysis of the total energy, band structure, density of states and the bulk modulus, we found that 3C-SiC was an indirect band gap semiconductor, the top of valence band was located at Γ point, and the bottom of conduction band was located at X point. The indirect band gap of 3C-SiC calculated by LDA, GGA, B3LYP and HSE06 was 1.34 eV, 1.44 eV, 2.88 eV and 2.26 eV, respectively. Especially for B3LYP and HSE06 methods which clearly calculated the energy splitting and the energy dispersion of both the top of valence band and the bottom of conduction band was in well agreement with the experimental data. These results will provide theoretical basis for the design and application of SiC materials.

First-Principles Study on Electronic Structure of 15R-SiC Polytypes

2014 ◽  
Vol 971-973 ◽  
pp. 77-80 ◽  
Author(s):  
Fu Chun Zhang ◽  
Ying Gao ◽  
Hong Wei Cui ◽  
Xing Xiang Ruan ◽  
Wei Hu Zhang
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Charge Density ◽  
Band Gap ◽  
Density Functional ◽  
Covalent Bond ◽  
Lattice Parameter ◽  
Pseudopotential Approach ◽  
Structure Density ◽  
Indirect Band Gap

To study the geometrical and electronic structure of 15R-SiC polytypes, the lattice parameter, band structure, density of states (DOS) and charge density of 15R-SiC are calculated by using density functional theory based on the plane wave pseudopotential approach, and electronic structure and ground properties of 15R-SiC are investigated by the calculated band structure and DOS, the results show that 15R-SiC is an indirect band gap semiconductor, with calculated indirect band gap width being 2.16 eV and band gap dependent on Si 3p and C 2p states. While charge density results show that Si-C bond is a hybrid bond semiconductor strong in covalent bond and weak in ionicity, characterized by intense sp3 hybrid characteristics, which is in accordance with the experimental results. The above mentioned results are considered as theoretical reference for design and application of SiC polytype materials.

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.

Increased Malleability in Tetragonal Zrx Ti1−x O2 Ternary Alloys: First-Principles Approach

2017 ◽  
Vol 72 (6) ◽  
pp. 567-572
Author(s):  
F. Ayedun ◽  
P.O. Adebambo ◽  
B.I. Adetunji ◽  
V.C. Ozebo ◽  
J.A. Oguntuase ◽  
...  
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Density Functional ◽  
Ternary Alloys ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Direct Band ◽  
Indirect Band Gap ◽  
Projector Augmented Wave ◽  
Alloying Effects

AbstractTetragonal phase of ZrxTi1−xO2ternary alloys is studied using generalized gradient approximation (GGA) projector augmented wave-based density functional theory (DFT). The calculations are used to characterize alloying effects of Zr substituting Ti in tutile TiO2. Band gap calculations show a direct band gap atx=0, while at other concentrations, an indirect band gap is observed. Electronic structure analysis shows that Zr alloying is capable of lowering the band gap transition of ZrxTi1−xO2atx=1 by the presence of an impurity state of transition metal Zr 5S2on the upper edge of the valence band. The addition of Zr also results in the corresponding increment in lattice constant with the material becoming more ductile and malleable.

Ab Initio Calculations of Structural, Electronic, and Mechanical Stability Properties of Magnesium Sulfide

2014 ◽  
Vol 69 (8-9) ◽  
pp. 403-410 ◽  
Author(s):  
Hai-Ying Wu ◽  
Ya-Hong Chen ◽  
Ping Zhou ◽  
Xiang-Yu Han ◽  
Zi-Jiang Liu
Keyword(s):  
Mechanical Stability ◽  
Theoretical Data ◽  
Cesium Chloride ◽  
Zero Temperature ◽  
Ambient Conditions ◽  
Generalized Gradient ◽  
Stability Properties ◽  
Generalized Gradient Approximation ◽  
Indirect Band Gap ◽  
Magnesium Sulfide

The structural, electronic, and mechanical stability properties of magnesium sulfide in different phases are presented using the plane wave pseudopotential method within the generalized gradient approximation. Eight different phases such as rocksalt (B1), zincblende (B3), wurtzite (B4), nickel arsenide (B8), cesium chloride (B2), PH4I-type (B11), FeSi-type (B28), and MnP-type (B31) are considered in great detail. The calculated ground-state properties of these phases are consistent with available experimental and theoretical data. It is found that MgS in the B1 and B8 phases are indirect band gap materials, the B3, B4, B11, B28, and B31 phases are all direct gap materials, while the B2 phase displays the metallic character. The B1, B3, B4, B8, B28, and B31 phases are mechanically stable at ambient conditions, but the B2 and B11 phases are mechanically unstable under zero pressure and zero temperature

Janus MSiGeN4 (M = Zr and Hf) monolayers derived from centrosymmetric β-MA2Z4: A first-principles study

2021 ◽  
Vol 42 (12) ◽  
pp. 122002
Author(s):  
Xiaoshu Guo ◽  
Sandong Guo
Keyword(s):  
Band Gap ◽  
Tensile Strain ◽  
Compressive Strain ◽  
Valence Band Maximum ◽  
Spin Splitting ◽  
Piezoelectric Response ◽  
Generalized Gradient ◽  
Thermal Stabilities ◽  
Out Of Plane ◽  
Indirect Band Gap

Abstract A two-dimensional (2D) MA2Z4 family with and phases has been attracting tremendous interest, the MoSi2N4 and WSi2N4 of which have been successfully fabricated ( Science 369, 670 (2020)). Janus monolayers have been achieved in many 2D families, so it is interesting to construct a Janus monolayer from the MA2Z4 family. In this work, Janus MSiGeN4 (M = Zr and Hf) monolayers are predicted from -MA2Z4, which exhibit dynamic, mechanical and thermal stabilities. It is found that they are indirect band-gap semiconductors by using generalized gradient approximation (GGA) plus spin-orbit coupling (SOC). With biaxial strain from 0.90 to 1.10, the energy band gap shows a nonmonotonic behavior due to a change of conduction band minimum (CBM). A semiconductor to metal transition can be induced by both compressive and tensile strains, and the phase transformation point is about 0.96 for compressive strain and 1.10 for tensile strain. The tensile strain can change the positions of CBM and valence band maximum (VBM), and can also induce the weak Rashba-type spin splitting near CBM. For MSiGeN4 (M = Zr and Hf) monolayers, both an in-plane and out-of-plane piezoelectric response can be produced, when a uniaxial strain in the basal plane is applied, which reveals the potential as piezoelectric 2D materials. The high absorption coefficients in the visible light region suggest that MSiGeN4 (M = Zr and Hf) monolayers have potential photocatalytic applications. Our works provide an idea to achieve a Janus structure from the MA2Z4 family, and can hopefully inspire further research exploring Janus MA2Z4 monolayers.

scholarly journals First Principles Study of Electronic and Optical Properties of Pristine and X (Cu, Ag And Au) Doped BiOBr

2018 ◽  
Vol 22 (2) ◽  
pp. 63-69 ◽  
Author(s):  
Samir Paudel ◽  
Puspa Raj Adhikari ◽  
Om Prakash Upadhyay ◽  
Gopi Chandra Kaphle ◽  
Anurag Srivastava
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Ab Initio Approach ◽  
Indirect Band Gap ◽  
Standard Density

The electronic structures and optical properties of pristine BiOBr and Cu, Ag and Au doped BiOBr have been analyzed by using a standard density functional theory based ab-initio approach employing generalized gradient approximation through revised Perdew Burke Ernzerhoff type parameterization. The calculation shows that both the doped and pristine BiOBr have indirect band gap, the band gap of the pristine BiOBr found 2.22eV, whereas band gap significantly reduced after doping Cu, Ag and Au on BiOBr. The band gap of Cu, Ag and Au doped BiOBr are 1.2eV, 0.9eV and 1.76eV respectively. The optical properties have been studied through dielectric function, both pure and doped BiOBr shows anisotropic nature. Journal of Institute of Science and TechnologyVolume 22, Issue 2, January 2018, page: 63-69 

scholarly journals Transparent All-Oxide Hybrid NiO:N/TiO2 Heterostructure for Optoelectronic Applications

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 988
Author(s):  
Chrysa Aivalioti ◽  
Alexandros Papadakis ◽  
Emmanouil Manidakis ◽  
Maria Kayambaki ◽  
Maria Androulidaki ◽  
...  
Keyword(s):  
Band Gap ◽  
Single Phase ◽  
Structural Disorder ◽  
Energy Band Gap ◽  
Nitrogen Doped ◽  
Nio Thin Film ◽  
Direct Band ◽  
Output Characteristics ◽  
Indirect Band Gap ◽  
P Type

Nickel oxide (NiO) is a p-type oxide and nitrogen is one of the dopants used for modifying its properties. Until now, nitrogen-doped NiO has shown inferior optical and electrical properties than those of pure NiO. In this work, we present nitrogen-doped NiO (NiO:N) thin films with enhanced properties compared to those of the undoped NiO thin film. The NiO:N films were grown at room temperature by sputtering using a plasma containing 50% Ar and 50% (O2 + N2) gases. The undoped NiO film was oxygen-rich, single-phase cubic NiO, having a transmittance of less than 20%. Upon doping with nitrogen, the films became more transparent (around 65%), had a wide direct band gap (up to 3.67 eV) and showed clear evidence of indirect band gap, 2.50–2.72 eV, depending on %(O2-N2) in plasma. The changes in the properties of the films such as structural disorder, energy band gap, Urbach states and resistivity were correlated with the incorporation of nitrogen in their structure. The optimum NiO:N film was used to form a diode with spin-coated, mesoporous on top of a compact, TiO2 film. The hybrid NiO:N/TiO2 heterojunction was transparent showing good output characteristics, as deduced using both I-V and Cheung’s methods, which were further improved upon thermal treatment. Transparent NiO:N films can be realized for all-oxide flexible optoelectronic devices.

scholarly journals Enhanced luminescence/photodetecting bifunctional devices based on ZnO:Ga microwire/p-Si heterojunction by incorporating Ag nanowires

2021 ◽  
Author(s):  
Mingming Jiang ◽  
Yang Liu ◽  
Ruiming Dai ◽  
Kai Tang ◽  
Peng Wan ◽  
...  
Keyword(s):  
Band Gap ◽  
Carrier Mobility ◽  
Lattice Mismatch ◽  
Semiconductor Materials ◽  
Large Lattice ◽  
Ag Nanowires ◽  
Large Lattice Mismatch ◽  
Enhanced Luminescence ◽  
Indirect Band Gap

Suffering from the indirect band gap, low carrier mobility, and large lattice mismatch with other semiconductor materials, one of the current challenges in Si-based materials and structures is to prepare...

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