First-principle calculations of the structure and elastic properties of GaAs under pressure

2009 ◽  
Vol 87 (2) ◽  
pp. 153-159 ◽  
Author(s):  
Hong-Ling Cui ◽  
Fen Luo ◽  
Xiang-Rong Chen ◽  
Guang-Fu Ji
Keyword(s):  
First Principles ◽  
Density Functional ◽  
First Principle ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Plane Wave Method ◽  
First Principle Calculations ◽  
Zinc Blende ◽  
Debye Temperatures ◽  
Theoretical Results

A first-principles plane-wave method with the ultrasoft pseudopotential scheme in the framework of density functional theory is performed to calculate the lattice parameters, the bulk modulus B0 and its pressure derivative B0' of the zinc-blende GaAs (ZB–GaAs), rocksalt GaAs (RS–GaAs), CsCl–GaAs, NiAs–GaAs, and wurtzite GaAs (WZ–GaAs). We also calculate the phase transition pressures between different phases, Debye temperatures, and the anisotropies. Our results are consistent with other theoretical results.

Structural and Elastic Properties of AlAs under Pressure from First-Principles Calculations

2011 ◽  
Vol 403-408 ◽  
pp. 84-87 ◽  
Author(s):  
Hong Ling Cui ◽  
Shi Jie Lv ◽  
Li Ben Li ◽  
Guang Fu Ji
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Wave Method ◽  
First Principles Calculations ◽  
Elastic Parameters ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Plane Wave Method ◽  
Zinc Blende ◽  
The Density Functional Theory

A first-principles plane wave method with the ultrasoft pseudopotential scheme in the frame of the density functional theory (DFT) is performed to calculate the structural and lattice parameters, the bulk modulus B0 and its pressure derivative B0' of the zinc-blende AlAs, rocksalt AlAs and NiAs-AlAs. The elastic parameters of the zinc-blende AlAs, rocksalt AlAs and NiAs- AlAs were calculated. We also calculate the phase transition pressures between different phases. Our results are satisfactory. Our results are consistent with other results.

Electronic and optical properties of AlN under pressure: DFT calculations

2017 ◽  
Vol 31 (02) ◽  
pp. 1650255
Author(s):  
Sahar Javaheri ◽  
Arash Boochani ◽  
Manuchehr Babaeipour ◽  
Sirvan Naderi
Keyword(s):  
Optical Properties ◽  
Electronic Properties ◽  
Dielectric Function ◽  
First Principles ◽  
Density Functional ◽  
Functional Theory ◽  
Zinc Blende ◽  
Rocksalt Phase ◽  
Optical And Electronic Properties ◽  
Theoretical Results

Structural, elastic, optical, and electronic properties of wurtzite (WZ), zinc-blende (ZB), and rocksalt (RS) structures of AlN are investigated using the first-principles method and within the framework of density functional theory (DFT). Lattice parameters, bulk modulus, shear modulus, Young’s modulus, and elastic constants are calculated at zero pressure and compared with other experimental and theoretical results. The wurtzite and zinc-blende structures have a transition to rocksalt phase at the pressures of 12.7 GPa and 14 GPa, respectively. The electronic properties are calculated using both GGA and EV-GGA approximations; the obtained results by EV-GGA approximation are in much better agreement with the available experimental data. The RS phase has the largest bandgap with an amount of 4.98 eV; by increasing pressure, this amount is also increased. The optical properties like dielectric function, energy loss function, refractive index, and extinction coefficient are calculated under pressure using GGA approximation. Inter-band transitions are investigated using the peaks of imaginary part of the dielectric function and these transitions mainly occur from N-2[Formula: see text] to Al-3[Formula: see text] levels. The results show that the RS structure has more different properties than the WZ and ZB structures.

First-Principles Study of H2O Adsorption on Oxygen-Covered Fe Surface

2012 ◽  
Vol 706-709 ◽  
pp. 1481-1484 ◽  
Author(s):  
Norio Nunomura ◽  
Satoshi Sunada
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Water Molecules ◽  
First Principle ◽  
Surface Oxygen ◽  
Functional Theory ◽  
First Principle Calculations ◽  
Oxygen Coverage ◽  
Adsorption Of Water

We present the results from first principle calculations of H2O adsorption on oxygen-covered Fe (100) surface. The calculations are based on a density-functional theory, surface modeling which uses supercell slab models. As a surface oxygen coverage increases, the surface is not activated, which makes the adsorption of water molecules on Fe surface unfavorable. It has been found that the surface covered oxygen exerts an influence on the adsorption of H2O molecule on Fe surface.

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 Triangle Terarylene as a Possible Optical Molecular Switch

2011 ◽  
Vol 311-313 ◽  
pp. 526-529
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Ji Xin Yin
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Molecular Switch ◽  
Optical Switches ◽  
Functional Theory ◽  
Closed Ring ◽  
Potential Applications ◽  
Homo Lumo ◽  
Non Equilibrium Green’S Function ◽  
Theoretical Results

Using non-equilibrium Green’s function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of a triangle terarylene(open- and closed-ring forms) optical molecular switch. The influence of the HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the quantum transport through the molecular device is discussed. Theoretical results show that the conductance of the closed-ring is 3-8 times larger than that of open-ring, which expect that this system can be one of good candidates for optical switches due to this unique advantage, and may have some potential applications in future molecular circuit.

First-Principles Calculations of the Structural, Electronic, Optical and Mechanical Properties of CdS, CdSe and CdTe

2013 ◽  
Vol 665 ◽  
pp. 302-306 ◽  
Author(s):  
Sheetal Sharma ◽  
Ajay Singh Verma
Keyword(s):  
Experimental Data ◽  
Density Functional ◽  
Full Potential ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Zinc Blende ◽  
Optical And Mechanical Properties ◽  
Good Agreement

The structural, electronic, optical and elastic properties of zinc-blende compounds (CdX, X = S, Se and Te), were studied using full-potential augmented plane wave plus local orbitals method (FP-LAPW+ lo) within density functional theory, using generalized gradient approximation (GGA). Geometrical optimization of the unit cell (lattice constant, bulk modulus and its pressure derivative) is in good agreement with experimental data. Results for band structures, density of states, and elastic constants (C11, C12 and C44) are presented. We also report our results on optical properties like the complex dielectric functions and the refractive index (n) of these compounds. Our results are in reasonable agreement with the available theoretical and experimental data.

scholarly journals ELASTIC PROPERTIES OF TRANSITION METAL DIOXIDES: XO2 (X = Ru, Rh, Os, andIr)

2008 ◽  
Vol 19 (08) ◽  
pp. 1269-1275 ◽  
Author(s):  
YANLING LI ◽  
ZHI ZENG
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Shear Modulus ◽  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Debye Temperatures ◽  
Metal Dioxides

The elastic properties of rutile transition metal dioxides XO2 ( X = Ru , Rh , Os , and Ir ) are investigated using first-principles calculations based on density functional theory. Elastic constants, bulk modulus, shear modulus, and Young's modulus as well as Possion ratio are given. OsO 2 and IrO 2 show strong incompressibility. The hardness estimated for these dioxides shows that they are not superhard solids. The obtained Debye temperatures are comparative to those of transition metal dinitrides or diborides.

An Ab Initio Study on Negative Differential Resistance in Pyrrole Trimer Molecular Device

2010 ◽  
Vol 152-153 ◽  
pp. 931-934
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Qiu Ping Wang
Keyword(s):  
Electronic Transport ◽  
First Principles ◽  
Negative Differential Resistance ◽  
Density Functional ◽  
Differential Resistance ◽  
Resonance Peak ◽  
Molecular Device ◽  
Transmission Resonance ◽  
Functional Theory ◽  
Theoretical Results

The electronic transport properties of pyrrole trimer sandwiched between two electrodes are investigated by using nonequilibrium Green’s function formalism combined first-principles density functional theory. Theoretical results show that the system manifests negative differential resistance (NDR) behavior. A detailed analysis of the origin of negative differential resistance has been given by observing the shift in transmission resonance peak across the bias window with varying bias voltage.

Electronic Structures of Vacancy Defective Chiral (6,2) SiC Nanotubes

2017 ◽  
Vol 896 ◽  
pp. 3-8
Author(s):  
Ke Jian Li ◽  
Hong Xia Liu
Keyword(s):  
Density Functional Theory ◽  
Silicon Carbide ◽  
Electronic Structures ◽  
Density Functional ◽  
First Principle ◽  
Defect Level ◽  
Functional Theory ◽  
Vacancy Defects ◽  
First Principle Calculations ◽  
Silicon Carbide Nanotubes

Vacancy defects are common defects formed in the syntheses of silicon carbide nanotubes (SiCNTs) and seriously impact the electronic structures of the nanotubes. With first-principle calculations based on density functional theory (DFT), vacancy defective (6,2) SiCNTs are studied. Vacancies form a pair of fivefold and ninefold rings. Carbon vacancy introduces an occupied defect level near the top of the valence band and an unoccupied level in the conduction band. Three defect levels are found in the band gap of the SiCNT with a silicon vacancy. These results are helpful for investigations on SiCNT devices and sensors.

scholarly journals Electronic Structure and Optical Properties ofGaAs1-xBixAlloy

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Xindong You ◽  
Renjie Zhou
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Optical Constants ◽  
Optical Transition ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Zinc Blende ◽  
Structural And Electronic Properties ◽  
Zinc Blende Structure

A first-principles study has been performed to investigate the structural and electronic properties of theGaAs1-xBixsystem. The simulations are based upon the generalized gradient approximation (GGA) within the framework of density functional theory (DFT). Calculations are performed to different Bi concentrations. The lattice constant ofGaAs1-xBixincreases with Bi concentration while the alloy remains in the zinc-blende structure. The band gap ofGaAs1-xBixclearly shrinks with the Bi concentration. The optical transition of Bi dopant in GaAs exhibits a red shift. Besides, other important optical constants, such as the dielectric function, reflectivity, refractive index, and loss function also change significantly.

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