Elastic and electronic properties of cubic cerium oxide under pressure via first principles

2014 ◽  
Vol 28 (14) ◽  
pp. 1450070 ◽  
Author(s):  
Z. W. Niu ◽  
B. Zhu ◽  
Y. Cheng ◽  
R. N. Song ◽  
G. F. Ji
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Local Density ◽  
Lattice Parameters ◽  
Total Density ◽  
Functional Theory ◽  
Young’S Moduli ◽  
Shear Wave Velocities ◽  
Total Density Of States ◽  
Good Agreement

The elastic and electronic properties of cubic structure CeO 2 under pressure are investigated in the frame of density functional theory (DFT). By using the local-density approximation (LDA) plus U( LDA +U) method with U = 6 eV, the calculated lattice parameters, bulk modulus and elastic properties of the cubic CeO 2 at 0 GPa and 0 K are in good agreement with the available experimental data. The pressure dependences of lattice parameters, bulk and shear modulus, Debye temperature, Young's moduli, Poisson's ratio and the compressional and shear wave velocities of the cubic CeO 2 are obtained successfully. In addition, the total density of states (TDOS) and the band gaps of the cubic CeO 2 under pressures are also investigated. By comparing the results of LDA and LDA+U, both the conventional LDA and the LDA+U methods can be used to describe the structure of the cubic CeO 2 due to the electronic localization of 4f-electron in Ce which is not so strong. However, the LDA+U approach can obtain a proper shape of the density of electronic states that agrees well with the measured values.

Structure, Electronic Properties, and Defects of GaN Using a Self-Consistent Molecular-Dynamics Method

1996 ◽  
Vol 449 ◽  
Author(s):  
Petra Stumm ◽  
D. A. Drabold
Keyword(s):  
Molecular Dynamics ◽  
Electronic Properties ◽  
Density Functional ◽  
Local Density ◽  
Functional Theory ◽  
Electronic Signatures ◽  
Self Consistent ◽  
Dynamics Simulations ◽  
Dynamics Method ◽  
Good Agreement

ABSTRACTMolecular dynamics simulations are employed to study defects in GaN. We use local basis density functional theory within the local density approximation where charge transfer between the ions is included in an approximate fashion. We find good agreement for the band structure of wurtzite and zincblende GaN compared to other recent calculations, suggesting the suitability of our method to describe GaN. A 96 atom GaN supercell is used to study the relaxations and electronic properties of common defects in the crystal structure, including Ga and N vacancies and antisites. We analyze the electronic signatures of these defects.

scholarly journals First Principle Calculations for Silver Halides AgBr, AgCl, and AgF

2021 ◽  
Vol 9 (2) ◽  
pp. 71-75
Author(s):  
Akram H. Taha
Keyword(s):  
Electronic Structures ◽  
Density Functional ◽  
Total Density ◽  
First Principle ◽  
Silver Halides ◽  
Functional Theory ◽  
First Principle Calculations ◽  
Almost All ◽  
Total Density Of States ◽  
Good Agreement

Density functional theory (DFT) coupled with ) method are carried out to calculate the electronic structures of AgX (X; Br, Cl, and F). The effect of hybridizing between 4d orbital of Ag element and the p orbitals of the X in the valence band plays a very important role in the total density of states configuration. The electronic structure has been studied and all results were compared with the experimental and theoretical values. The importance of this work is that there is insufficient studies of silver halides corresponding the great importance of these compounds. Almost all the results were consistent with the previous studies mentioned here. We found the band gap of AgX to be 2.343 eV, 2.553 eV, and 1.677 eV for AgBr, AgCl, and AgF respectively which are in good agreement with the experimental results.      

FIRST-PRINCIPLES STUDY OF THE ELECTRONIC PROPERTIES OF GaAs(114)A (2×1) SURFACE

2006 ◽  
Vol 20 (20) ◽  
pp. 1275-1285 ◽  
Author(s):  
SANJUN WANG ◽  
YOULIN SONG ◽  
XIANLIN ZHAO ◽  
JINMING LI ◽  
JINHAI LIU ◽  
...  
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Total Density ◽  
High Symmetry ◽  
Surface Band ◽  
Functional Theory ◽  
Surface Brillouin Zone ◽  
Total Density Of States ◽  
Dimensional Surface

The electronic properties of the GaAs(114)A (2×1) surface are studied by using the first-principles method within density functional theory (DFT). The reconstructed geometric structure and surface band structure, together with the total density of states, are presented respectively. Our results show that the surface properties of GaAs(114)A turns to be semiconductive after α2(2×1) or β2(2×1) reconstruction. The gap between the highest occupied states and the lowest unoccupied states is 0.8 and 0.9 eV for α2(2×1) and β2(2×1) reconstruction respectively. Furthermore, the dispersion properties along the high symmetry lines of the two-dimensional surface Brillouin zone are also discussed.

scholarly journals Comparative study of the structural and electronic properties of orthorhombic CH3NH3PbI3 hybrid perovskite for solar cell applications

2021 ◽  
Vol 40 (4) ◽  
pp. 616-622
Author(s):  
T.C. Chibueze
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Local Density ◽  
Total Density ◽  
Generalized Gradient ◽  
Lead Iodide ◽  
Functional Theory ◽  
Hybrid Perovskite ◽  
Structural And Electronic Properties ◽  
Direct Band

The structural and electronic properties of orthorhombic methyl ammonium lead iodide (CH3NH3PbI3 ) were investigated using the first principles density functional theory within the local density approximation (LDA) and the generalized gradient approximation (GGA).The lattice parameters obtained using the GGA were slightly greater than that obtained using the LDA. The total density of states and the electronic structure of the compound show that it is a direct band gap semiconductor. Our results are in agreement with the previous experimental and theoretical results and suggests that orthorhombic CH3NH3PbI3 compound is very promising in photovoltaic energy harvesting.

scholarly journals Ab-initio study of the orthorhombic ndmno3 perovskite

2014 ◽  
Vol 70 (a1) ◽  
pp. C1806-C1806
Author(s):  
Samir Bentata ◽  
Bouabdellah Bouadjemi ◽  
Tayeb Lantri ◽  
Wissem Benstaali
Keyword(s):  
Density Functional ◽  
Electronic Band Structure ◽  
Total Density ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Functional Theory ◽  
Half Metallic ◽  
Generalized Gradient Approximation ◽  
Ferromagnetic Ground State ◽  
Total Density Of States

We investigate the structural, electronic and magnetic properties of the orthorhombic Perovskite oxyde NdMnO3 through density-functional-theory (DFT) calculations using both generalized gradient approximation GGA+U, where U is on-site Coulomb interaction correction. The electronic band structure, the partial and total density of states (DOS) and the magnetic moment are determined. The results show a half-metallic ferromagnetic ground state for the orthorhombic NdMnO3.

Ab intio Investigations of Lattice Parameters in ZnMgO Alloys

2009 ◽  
Vol 1201 ◽  
Author(s):  
Markus Heinemann ◽  
Marcel Giar ◽  
Christian Heiliger
Keyword(s):  
Density Functional ◽  
Local Density ◽  
Density Functional Theory Calculations ◽  
Lattice Parameters ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Lattice Constants ◽  
Exchange Correlation ◽  
Vegard’S Law ◽  
Constant Unit

AbstractWe perform density functional theory calculations to determine equilibrium lattice parameters of wurtzite Zn1-xMgxO alloys for Mg concentrations x ranging from 0 to 31.25 %. We use the local density approximation (LDA) as well as the generalized gradient approximation (GGA) for the exchange correlation functional. For the lattice constants a and c we find a deviation from Vegard's law and a constant unit cell volume independent of the Mg concentration.

FIRST-PRINCIPLES STUDY OF THE ELECTRONIC, LINEAR, AND NONLINEAR OPTICAL PROPERTIES OF Li(Nb, Ta)O3

2010 ◽  
Vol 24 (32) ◽  
pp. 6277-6290 ◽  
Author(s):  
SULEYMAN CABUK
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Energy Gap ◽  
Local Density ◽  
Theoretical Calculations ◽  
Total Density ◽  
Functional Theory ◽  
Experimental Values ◽  
Electron Energy Loss

We investigate the energy band structure, total density of states, the linear, nonlinear optical (NLO) response, and the electron energy-loss spectrum for Li(Nb, Ta)O 3 using first principles calculations based on density functional theory in its local density approximation. Our calculation shows that these compounds have similar structures. The indirect band gaps of 3.39 eV (LiNbO3) and 3.84 eV (LiTaO3) at the Γ–Z direction in the Brillouin zone are found. A simple scissor approximation is applied to adjust the band energy gap from the calculations to match the experimental values. The optical spectra are analyzed and the origins of some of the peaks in the spectra are discussed in terms of calculated electronic structure. Calculations are reported for the frequency-dependent complex second-order NLO susceptibilities [Formula: see text] up to 10 eV and for zero-frequency limit [Formula: see text]. The results are compared with the theoretical calculations and the available experimental data.

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.

STRUCTURAL, ELASTIC AND ELECTRONIC PROPERTIES OF OXYGEN SUBSTITUTION IN CUBIC Zr3N4 AND Ti3N4

2013 ◽  
Vol 27 (18) ◽  
pp. 1350095 ◽  
Author(s):  
YI-MING CHEN ◽  
WEI CHENG ◽  
BIN LIAO ◽  
XU ZHANG
Keyword(s):  
Fermi Level ◽  
Electronic Properties ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Shear Moduli ◽  
Young’S Moduli ◽  
The Density Functional Theory ◽  
Oxygen Substitution ◽  
Nitrogen Bond

The structural, elastic and electronic properties of O-doped and un-doped cubic Zr 3 N 4 and Ti 3 N 4 are studied by first principles calculations based on the density functional theory. The bulk and shear moduli, as well as Young's moduli, decrease after doping with oxygen, which is due to the lengthening of the metal-nitrogen bond as well as the inflation of the cell volume. The changes in elastic properties are consistent with available experimental results. Both nitrides change from brittle to ductile when doped with oxygen, and all materials can be regarded as being elastic isotropic. The band structure and density of states are calculated to discuss the electronic properties of O-doped cubic Zr 3 N 4 and Ti 3 N 4, the presence of oxygen has significant influence on the electronic structure near the Fermi level. The gap at Fermi level is vanished which confirms the metallic character when O is introduced into nitrides. It means that doping with oxygen will have important effects on the optical properties of Zr and Ti nitrides.

Electronic, Optical and Vibrational Properties of B3N3H6 from First-Principles Calculations

2021 ◽  
Author(s):  
Yun-Dan Gan ◽  
Han Qin ◽  
Fu-Sheng Liu ◽  
Zheng-Tang Liu ◽  
Cheng lu Jiang ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Structural Parameters ◽  
Vibrational Properties ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Conductivity Loss ◽  
Good Agreement

Abstract The electronic, optical and vibrational properties of B3N3H6 have been calculated by means of first-principles density functional theory (DFT) calculations within the generalized gradient approximation (GGA) and the local density approximation (LDA). The calculated structural parameters of B3N3H6 are in good agreement with experimental work. With the band structure and density of states (DOS), we have analyzed the optical properties including the complex dielectric function, refractive index, absorption, conductivity, loss function and reflectivity. By the contrast, it is found that on the (001) component and (100) component have obvious optical anisotropy. Moreover, the vibrational properties have been obtained and analyzed.

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