scholarly journals Structural and Electronic Properties of Orthorhombic Phase Bi2Se3 Based On First-Principles Study

2019 ◽  
Vol 16 (2) ◽  
pp. 77 ◽  
Author(s):  
Muhammad Zamir Mohyedin ◽  
Afiq Radzwan ◽  
Mohammad Fariz Mohamad Taib ◽  
Rosnah Zakaria ◽  
Nor Kartini Jaafar ◽  
...  
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Computer Code ◽  
First Principles Calculation ◽  
Generalized Gradient ◽  
Exchange Correlation ◽  
Percentage Difference ◽  
Structural And Electronic Properties

Bi2Se3 is one of the promising materials in thermoelectric devices and very useful out of environmental concern due to its efficiency to perform at room temperature. Based on the first-principles calculation of density functional theory (DFT) by using CASTEP computer code, structural and electronic properties of Bi2Se3 were investigated. The calculation is conducted within the exchange-correlation of local density approximation (LDA) and generalized gradient approximation within the revision of Perdew-Burke-Ernzerhof (GGA-PBE) functional. It was found that the results are consistent with previous works of theoretical study with small percentage difference. LDA exchange-correlation functional method is more accurate and have a better agreement than GGA-PBE to describe the structural properties of Bi2Se3 which consist of lattice parameters. LDA functional also shown more accurate electronic structure of Bi2Se3 that consist of band structure and density of states (DOS) which consistent with most previous theoretical works with small percentage difference. This study proves the reliability of CASTEP computer code and show LDA exchange-correlation functional is more accurate in describing the nature of Bi2Se3 compared to the other functionals.

Research on the Elastic Property of Three New Superhard Materials

2013 ◽  
Vol 302 ◽  
pp. 165-169
Author(s):  
Feng Li ◽  
Qun Hui ◽  
Jing Ao ◽  
Jin Wang ◽  
Chun Mei Li ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Correlation Effect ◽  
Superhard Materials ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Spatial Anisotropy ◽  
Plane Wave Method ◽  
Exchange Correlation

In this thesis, elastic properties of three BCN superhard materials with different structures are computed by using CASTEP software developed according to the first principles which are based on density functional theory (DFT) and plane wave method. CA-PZ of local density approximation (LDA) and PBE of generalized gradient approximation (GGA) are adopted to describe the exchange-correlation effect between electrons. The results are compared with other findings and c-BN data. Through analysis, it is found that the spatial anisotropy do exist in the Young's modulus of single crystals all three BCN compounds.

First-principles investigation of the vibrational properties of 3-tert-butylcyclohexene

Open Physics ◽  
2010 ◽  
Vol 8 (5) ◽  
Author(s):  
Katalin Gaál-Nagy
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Vibrational Properties ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Density Functional Perturbation Theory ◽  
Characteristic Modes ◽  
Correlation Potential

AbstractI present a first-principles investigation of the vibrational properties of the chiral molecule 3-tert-butylcyclohexene. The vibrational density of states (vDOS) of the two existing conformers has been calculated ab initio within the framework of density-functional theory and density-functional perturbation theory, using both the local-density approximation and the generalized-gradient approximation for the exchange-correlation potential. The vDOS of the two conformers are very similar. The vDOS has been investigated with respect to contributions of the cyclohexene ring and the tert-butyl group and also regarding the localization of vibrational modes. Additionally, the eigendisplacements of characteristic modes of 3-tert-butylcyclohexene have been analyzed.

scholarly journals Insight into Physical and Thermodynamic Properties of X3Ir (X = Ti, V, Cr, Nb and Mo) Compounds Influenced by Refractory Elements: A First-Principles Calculation

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 104 ◽  
Author(s):  
Dong Chen ◽  
Jiwei Geng ◽  
Yi Wu ◽  
Mingliang Wang ◽  
Cunjuan Xia
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
First Principles Calculation ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Debye Temperatures ◽  
Experimental Parameters ◽  
Experimental Values

The effects of refractory metals on physical and thermodynamic properties of X3Ir (X = Ti, V, Cr, Nb and Mo) compounds were investigated using local density approximation (LDA) and generalized gradient approximation (GGA) methods within the first-principles calculations based on density functional theory. The optimized lattice parameters were both in good compliance with the experimental parameters. The GGA method could achieve an improved structural optimization compared to the LDA method, and thus was utilized to predict the elastic, thermodynamic and electronic properties of X3Ir (X = Ti, V, Cr, Nb and Mo) compounds. The calculated mechanical properties (i.e., elastic constants, elastic moduli and elastic anisotropic behaviors) were rationalized and discussed in these intermetallics. For instance, the derived bulk moduli exhibited the sequence of Ti3Ir < Nb3Ir < V3Ir < Cr3Ir < Mo3Ir. This behavior was discussed in terms of the volume of unit cell and electron density. Furthermore, Debye temperatures were derived and were found to show good consistency with the experimental values, indicating the precision of our calculations. Finally, the electronic structures were analyzed to explain the ductile essences in the iridium compounds.

scholarly journals A study on structural and electronic properties of GaAs1-xNx and GaAs1-xBix alloys

2016 ◽  
Vol 4 (1) ◽  
pp. 6
Author(s):  
Metin Aslan ◽  
Battal Gazi Yalcin
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Local Density ◽  
Nitrogen Concentration ◽  
Potential Method ◽  
Generalized Gradient ◽  
Wide Range ◽  
Structural And Electronic Properties ◽  
Semiconductor Alloy ◽  
Ternary Semiconductor

<p>We have performed first principles method to investigate structural and electronic properties of GaAs<sub>1-x</sub>N<sub>x</sub> and GaAs<sub>1-x</sub>Bi<sub>x</sub> ternary semiconductor alloy using Density Functional Theory and pseudo potential method within the Generalized Gradient Approximations and Local Density Approximation. The Zinc-Blende phase is found stable for GaAsN and GaAsBi alloys. In this study we investigate the both bowing parameters changing with Bismuth concentration in GaAsBi and Nitrogen concentration in GaAsN alloys. By using the bowing parameter of GaAsBi and GaAsN alloys we obtained the bandgap energies for all x concentrations (0 &lt; x &lt; 1) and lattice constant of both alloys which are important for wide range device application. For studied materials, lattice parameters and band gap energies are compared with available theoretical and experimental works.</p>

Electronic properties of two-dimensional ZnO atomically sheet on Cu substrate: a first-principles study

2014 ◽  
Vol 28 (26) ◽  
pp. 1450204 ◽  
Author(s):  
Fayyaz Hussain ◽  
M. Imran ◽  
Y. Q. Cai ◽  
Hafeez Ullah ◽  
Abdul Shakoor ◽  
...  
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Schottky Contact ◽  
First Principles Calculation ◽  
Two Dimensional ◽  
Cu Substrate ◽  
Conduction Bands ◽  
Structural And Electronic Properties ◽  
Potential Applications

Bulk ZnO has traditionally been regarded as multifunctional materials for energy and optoelectronics applications. Recently, exploring this material at the nanoscale has been reported and seeking a proper substrate is highly desired. In this work, the structural and electronic properties of graphene like ZnO two-dimensional (2D) monolayer are investigated by first principles calculation based on density functional theory. The alignment of the valence and conduction bands of ZnO with the state of Cu substrate is analyzed. Particularly the attention has been focused on the establishment of a Schottky contact and interfacial charge transfer between the 2D ZnO monolayer and Cu substrate. It is predicted that the electronic charges are accumulated on the Zn and O atoms due to d–d hybridization between Cu and Zn . Our study reveals that the significant interaction between the ZnO and Cu can greatly modify the electronic properties of the ZnO and suggests potential applications in nanoelectronic devices.

FIRST-PRINCIPLES STUDY OF STRUCTURAL AND ELECTRONIC PROPERTIES OF SrLiSb UNDER HIGH PRESSURE

2012 ◽  
Vol 26 (29) ◽  
pp. 1250151
Author(s):  
Z. H. YU ◽  
C. Y. LI ◽  
H. Z. LIU
Keyword(s):  
High Pressure ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Geometry Optimization ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Electronic Phase ◽  
Structural And Electronic Properties

Using the first-principles plane wave pseudopotential method, the structural and electronic properties of intermetallic compound SrLiSb have been studied within generalized gradient approximation in the frame of density functional theory. The calculations of lattice parameters are in well agreement with the available experimental data. The geometry optimization results indicated the compressibility of SrLiSb is anisotropic under high pressure. The energy band structure and density of states of SrLiSb were also calculated, indicating that SrLiSb has an electronic phase transition from direct-gap semiconductor to indirect-gap semiconductor at approximate 8 GPa.

First Principles Calculations to Describe Zirconia Pseudopolymorphs

1997 ◽  
Vol 492 ◽  
Author(s):  
G. Jomard ◽  
T. Petit ◽  
L. Magaud ◽  
A. Pasturel
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Oxygen Vacancies ◽  
Local Density ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Pseudopotential Theory ◽  
Structural And Electronic Properties ◽  
Gradient Corrections ◽  
Made In

ABSTRACTThe structural and electronic properties of four different structures of zirconia (ZrO2) are studied using ab initio total energy calculations. The calculations are made in the framework of density functional (DFT) and pseudopotential theory. We compare results given within the LDA (Local Density Approximation) and including Generalized Gradient Corrections (GGCs) in the Perdew Wang and Perdew Becke formalisms. We present results for pure and defective zirconia (oxygen vacancies and Zr substitution by Fe) showing the effects of such point defects on tne relative structural stabilities of the different pseudopolymorphs.

scholarly journals Structural and electronic properties of boron- bismuth compound under pressure

2016 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Salah Daoud ◽  
Noudjoud Labgaa
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Pressure Effect ◽  
Local Density ◽  
Band Gaps ◽  
First Principles Calculations ◽  
Density Func Tional Theory ◽  
Exchange Correlation ◽  
Bismuth Compound ◽  
Structural And Electronic Properties

<p>In the present work, we report first principles calculations of the pressure effect on the structural and electronic properties of Boron- Bismuth (BBi) compound in its zincblende phase. The pseudopotential plane wave (PPW) method in the framework of the density func-tional theory (DFT) within the local density approximation for the exchange-correlation functional, and the Hartwigzen-Goedecker-Hutter (HGH) scheme for the pseudopotential were used in the calculation. The unit cell volume, the molecular and crystal densities, the equation of state and also the linear and quadratic pressure coefficients of the energy band-gaps are investigated.</p>

A DFT study of structural and electronic properties of Zn1−xSbxTe with x = (0.25,0.50,0.75)

2017 ◽  
Vol 31 (01) ◽  
pp. 1650249
Author(s):  
Diwaker ◽  
Ashwani Kumar
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Text Type ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
The Density Functional Theory ◽  
Structural And Electronic Properties ◽  
Sb Doping

In the present work, we report the structural and the electronic properties of the alloy [Formula: see text] with [Formula: see text] and [Formula: see text]. Ab initio calculations are based upon the density functional theory with generalized gradient approximation and Perdew–Burke–Ernzerhof (PBE) exchange–correlation functional. In our calculations, we found that antimony (Sb) doping in zinc telluride (ZnTe) system introduces some bands which mainly originate from [Formula: see text]- and [Formula: see text]-states of Te and Sb atom and are primarily responsible for [Formula: see text]-type and [Formula: see text]-type conductivity.

Optical Properties of Heterodiamond BC3 from First-Principles

2013 ◽  
Vol 749 ◽  
pp. 551-555 ◽  
Author(s):  
Lei Li ◽  
Wen Xue Li ◽  
Dong Han ◽  
She Wei Xin ◽  
Yi Yang ◽  
...  
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
First Principles Calculation ◽  
Optical Absorption Coefficient ◽  
Generalized Gradient ◽  
Exchange Correlation ◽  
Electron Deficiency

First principles calculation for optical properties of a tetragonal BC3 (t-BC3) are performed through the pseudopotential density functional method. The exchange correlation potential is treated by the Perdew-Burke-Eruzerhof form of generalized gradient approximation. The basic optical constants including the real and imaginary parts of the dielectric function, the optical absorption coefficient, the reflectivity and the energy loss function were calculate in detail by this method. The results indicate that the t-BC3 is an optical anisotropic crystal and its electron-deficiency characteristic can cause some features in low energy region.

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