Cálculo de la estructura electrónica de la superred (GaN)4(RuN)4

Se investigaron las propiedades estructurales y electrónicas de la superred de periodo corto (GaN)4(RuN)4 calculadas en estructura wurtzita con orientación (0001), usando un cálculo de primeros principios dentro de la DFT (Density Functional Teory). Se utilizó el método FP-LAPW (Full Potential Linearized Augmented Plane Waves), como fue implementado en el código WIEN2k. Los efectos correlación e intercambio fueron tratados usando la GGA (Generalized Gradient Approximation) de Perdew, Burke y Ernzerhof. Para determinar los mejores parámetros en estructura wurtzita se optimizó la energía total como una función: i) el volumen de la celda unitaria, ii) la razón c/a y iii) la coordenada z de los átomos de Ga y Ru. Se hace un estudio detallado de la densidad de estados y estructura de bandas; se encontró que la superred (GaN)4(RuN)4 presenta un comportamiento metálico. En el nivel de Fermi, la contribución a la densidad de estados se debe principalmente a los orbitales atómicos d de Ru.

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Structural, Electronic and Magnetic Properties of CaSe Doped with 3d (V, Cr and Mn)

SPIN ◽

10.1142/s2010324721500260 ◽

2021 ◽

Author(s):

Youcef Daoudi ◽

Hadj Moulay Ahmed Mazouz ◽

Brahim Lagoun ◽

Ali Benghia

Keyword(s):

Magnetic Properties ◽

Transition Metal ◽

Density Functional ◽

Magnetic Moments ◽

Plane Waves ◽

Double Exchange ◽

Spin Splitting ◽

Full Potential ◽

Generalized Gradient ◽

Electronic And Magnetic Properties

We report first-principles investigation on structural, electronic and magnetic properties of 3d transition metal element-doped rock-salt calcium selenide Ca[Formula: see text]TMxSe (TM = V, Cr and Mn) at concentrations [Formula: see text] = 0.0625, 0.125 and 0.25. We performed the calculations in the framework of the density functional theory (DFT) using the full-potential linearized augmented plane waves plus local orbitals (FP-LAPW+lo) method within the Wu–Cohen generalized gradient approximation (WC-GGA) for the structural optimization and the Tran–Blaha modified Becke–Johnson (TBmBJ) potential for the electronic and the magnetic properties. The computed spin-polarized band structures and densities of states show that Ca[Formula: see text]CrxSe compounds at all studied concentrations are half-metallic ferromagnets with a complete spin polarization of 100% at Fermi-level while the Ca[Formula: see text]VxSe and Ca[Formula: see text]MnxSe are ferromagnetic semiconductors. The total magnetic moments for Ca[Formula: see text]VxSe, Ca[Formula: see text]CrxSe, and Ca[Formula: see text]MnxSe show the integer values of 3[Formula: see text][Formula: see text], 4[Formula: see text][Formula: see text], and 5[Formula: see text][Formula: see text], respectively, with a major contribution of transition metal elements (TM) in the total magnetization. Also, we reported the calculated exchange constants [Formula: see text] and [Formula: see text] and the band edge spin splitting of the valence ([Formula: see text]) and conduction ([Formula: see text]) bands. The ferromagnetism of these compounds is due to the super-exchange and the double-exchange mechanisms in addition to the strong p–d exchange interaction. Therefore, the predicted results indicate that the diluted Ca[Formula: see text]TMxSe (TM = V, Cr, Mn) compounds are suitable candidates for a possible application in the field of spintronic technology.

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Theoretical investigations on structural and optoelectronic properties of Bismuth oxyhalides

International Journal of Modern Physics B ◽

10.1142/s0217979221503033 ◽

2021 ◽

Author(s):

Muhammad Aamir Iqbal ◽

Maria Malik ◽

Wajeehah Shahid

Keyword(s):

Density Functional ◽

Functional Materials ◽

Optoelectronic Properties ◽

Full Potential ◽

Generalized Gradient ◽

Electronic Band ◽

Generalized Gradient Approximation ◽

Wide Range ◽

Bandgap Semiconductors ◽

Structural And Optoelectronic Properties

Density functional theory’s (DFT) full potential linearized augmented plane wave method has been used to explore the structural and optoelectronic properties of bismuth-based tetragonal BiOCl, BiOBr and BiOI semiconductors. The generalized gradient approximation (GGA) has been used for structural optimization to approximate lattice constants and bulk moduli, which are found to be consistent with the current literature. Electronic band structures are computed using the modified Becke and Johnson generalized gradient approximation (mBJ) and within the Engel and Vosko generalized gradient approximation (EV-GGA), respectively. Based on the band structure analysis, these functional materials are indirect bandgap semiconductors with a wide range of potential applications. In addition, optical properties are also computed within mBJ and found to be appealing for optoelectronics and photocatalysis.

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The study of structural, elastic, electronic and optical properties of CsYx I(1 − x)(Y = F, Cl, Br) using density functional theory

Materials Science-Poland ◽

10.1515/msp-2017-0017 ◽

2017 ◽

Vol 35 (1) ◽

pp. 197-210 ◽

Cited By ~ 1

Author(s):

Shabeer Ahmad Mian ◽

Muhammad Muzammil ◽

Gul Rahman ◽

Ejaz Ahmed

Keyword(s):

Optical Properties ◽

Density Functional ◽

Full Potential ◽

Generalized Gradient ◽

Functional Theory ◽

Augmented Plane Wave ◽

Generalized Gradient Approximation ◽

G Ratio ◽

Linearized Augmented Plane Wave ◽

Incremental Addition

AbstractThe structural, electronic, elastic and optical properties of CsYx I(1 − x)(Y = F, Cl, Br) are investigated using full potential linearized augmented plane wave (FP-LAPW) method within the generalized gradient approximation (GGA). The ground state properties such as lattice constant (ao) and bulk modulus (K) have been calculated. The mechanical properties including Poisson’s ratio (σ), Young’s modulus (E), anisotropy factor (A) and shear modulus (G) were also calculated. The results of these calculations are comparable with the reported experimental and theoretical values. The ductility of CsYx I(1 − x) was analyzed using Pugh’s rule (B/G ratio) and Cauchy’s pressure (C12−C44). Our results revealed that CsF is the most ductile among the CsYxI(1 − x)(Y = F, Cl, Br) compounds. The incremental addition of lighter halogens (Yx) slightly weakens the strength of ionic bond in CsYxI(1 − x). Moreover, the optical transitions were found to be direct for binary and ternary CsYxI(1 − x). We hope that this study will be helpful in designing binary and ternary Cs halides for optoelectronic applications.

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A Comparative Study of the Influence of the Local Density Approximation and the Generalized Gradient Approximation on the Calculated Properties of the III-Nitride (110) Surfaces

MRS Proceedings ◽

10.1557/proc-639-g11.46 ◽

2000 ◽

Vol 639 ◽

Author(s):

H. W. Leite Alves ◽

J. L. A. Alves ◽

R. A. Nogueira ◽

J. R. Leite

Keyword(s):

Local Density Approximation ◽

Density Functional ◽

Local Density ◽

Structural Parameters ◽

Full Potential ◽

Density Approximation ◽

Generalized Gradient ◽

Generalized Gradient Approximation ◽

The Density Functional Theory ◽

Supercell Model

ABSTRACTWe present a systematic theoretical study of several III-nitride (110) surfaces based on accurate parameter-free, self-consistent total energy and force calculations using the density functional theory, the local density approximation (LDA), as parametrized by Perdew and Zunger, and the generalized gradient approximation (GGA), as proposed by Perdew, Burke, and Ernzerhof, for the exchange-correlation term; we use the Full Potential Linear Augmented Plane Wave (FPLAPW) approach (WIEN-97 code) associated with the slab supercell model to simulate the (110) surface. We studied BN, AlN, GaN, InN and compared the theoretical results as related to the use of the LDA and the GGA. We conclude that although the results for both approximations are similar, differences in structural parameters may be as large as 10%.

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Calculation of Structural, Electronic and Optical Properties of Double Perovskite Ca2CrNbO6

SPIN ◽

10.1142/s2010324721500120 ◽

2021 ◽

pp. 2150012

Author(s):

W. Benosmane ◽

S. Benatmane ◽

R. Bentata ◽

W. Benstaali

Keyword(s):

Density Functional ◽

Double Perovskite ◽

Full Potential ◽

Generalized Gradient ◽

Functional Theory ◽

Augmented Plane Wave ◽

Generalized Gradient Approximation ◽

Spin Polarized ◽

Optical Dielectric ◽

Linearized Augmented Plane Wave

The structural electronic and magnetic properties of the double perovskite Ca2CrNbO6 in the cubic structure are investigated using the empirical full-potential linearized augmented plane wave (FP-LAPW) method within the framework of the spin-polarized density functional theory (DFT). These properties are calculated using the Generalized Gradient Approximation (GGA), [Formula: see text] and modified Becke–Johnson mBJ-GGA. In addition, the real and imaginary parts of the optical dielectric function and the reflectivity, and the refractive spectra are computed and the main features shown by their spectra are ascertained on the base of the investigation of density of states.

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FIRST-PRINCIPLES INVESTIGATION OF SnO2 AT HIGH PRESSURE

International Journal of Modern Physics B ◽

10.1142/s0217979205032644 ◽

2005 ◽

Vol 19 (27) ◽

pp. 4081-4092 ◽

Cited By ~ 15

Author(s):

F. EL HAJ HASSAN ◽

A. ALAEDDINE ◽

M. ZOAETER ◽

I. RACHIDI

Keyword(s):

Total Energy ◽

Density Functional ◽

Tin Dioxide ◽

Correlation Energy ◽

Structural Phase ◽

Cubic Phase ◽

Full Potential ◽

Generalized Gradient ◽

Exchange Correlation ◽

Generalized Gradient Approximation

The ground state properties and the structural phase transformation of tin dioxide ( SnO 2) have been investigated using first principle full potential-linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). We used local density approximation (LDA) and the generalized gradient approximation (GGA), which are based on exchange-correlation energy optimization, to optimize the internal parameters by relaxing the atomic positions in the force directions and to calculate the total energy. For band structure calculations, we utilized both the Engel-Vosko's generalized gradient approximation (EVGGA), which optimizes the exchange-correlation potential, and also GGA. From the obtained band structures, the electron (hole) valance and conduction effective masses are deduced. For compressed volumes SnO 2 is shown to undergo two structural phase transitions with increasing pressure from the rutile- to the CaCl 2-type phase at 12.4 GPa and to a cubic phase, space group [Formula: see text] at 22.1 GPa. The calculated total energy allowed us to investigate several structural properties, in particular, the equilibrium lattice constants, bulk modulus, cohesive energy, interatomic distances and the angles between different atomic bonds. In addition, we discuss the bonding parameter in term of charge density, which show the localization of charge around the anion side.

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Optimizing Configurations for Determining the Electromagnetic Properties of CsFeF3, NaFeF3, and RbFeF3 Fluorides: GGA vs GGA+U and TB-mBj Approaches

Annals of West University of Timisoara - Physics ◽

10.2478/awutp-2020-0005 ◽

2020 ◽

Vol 62 (1) ◽

pp. 71-94

Author(s):

Filalli Sihem ◽

Hamdad Noura

Keyword(s):

Density Functional ◽

Electronic Band Structure ◽

Structural Parameters ◽

Magnetic Moments ◽

Plane Waves ◽

Electromagnetic Properties ◽

Full Potential ◽

Generalized Gradient ◽

Electronic Band ◽

Covalent Interaction

AbstractThe structural, electronic and magnetic properties of (Cubic Pm-3m, Hexagonal-4H, orthorhombic Pnma, and orthorhombic Pbnm) phases of AFeF3 Fluorides (A = Cs, Na, and Rb) are reported theoretically using full potential linearized augmented plane waves method within the density functional theory (DFT). Using different exchange–correlation approximations including the generalized gradient approximation (PBE-GGA, WC-GGA, and PBEsol-GGA), also (GGA) with Hubbard potential (GGA + U) and The modified Becke Johnson potential (mBJ), we carried to determine various physical properties. The Calculations revealing that the estimated structural parameters are reliable with the experimentally reported data. Magnetically all these intermetallics are Ferromagnetic (FM). The ground-state energy of different magnetic phases studied showed that the magnetic moments are evaluated per atom, and overestimated by (GGA+U). Transfer charge reveals a strong covalent interaction between Fe-Fe atoms. Their electronic band structure and density of states indicate insulator behavior.

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Elastic properties and electronic structure of the Ni3Sb (cF16) intermetallic

MRS Proceedings ◽

10.1557/opl.2016.62 ◽

2016 ◽

Vol 1816 ◽

Cited By ~ 1

Author(s):

Críspulo E. Deluque ◽

Susana B. Ramos ◽

Armando J. Fernández

Keyword(s):

Elastic Properties ◽

Density Functional ◽

Degrees Of Freedom ◽

Local Density ◽

Structural Parameters ◽

Plane Waves ◽

Full Potential ◽

Generalized Gradient ◽

Electronic Density ◽

Local Density Approximations

ABSTRACTThe possibilities of Ni as contact material in electronic applications has motivated the interest on the intermetallic phases of the Ni-Sb system, in relation to their use in lead free micro-soldering processes. In this work, a detailed theoretical study of the cohesive and thermodynamic properties of the compound Ni3Sb in the (cF16) Fm-3m structure is reported. To this aim, the Full Potential Linearized Augmented Plane Waves method, within the framework of the Density Functional Theory and both Generalized Gradient and Local Density approximations, has been applied. The structural parameters, cohesive and elastic properties of this compound and its constituent elements have been determined. In particular, the equilibrium structural properties are determined through the minimization of the energy, including the full relaxation of the internal degrees of freedom of the cell. It is shown that the calculated properties agree well with the available experimental data. Moreover, various contributions to the electronic density of sates are studied. On this basis, a discussion is presented of the bonding characteristics of this compound, in the framework of the current ideas about cohesion in p-d bonded intermetallics.

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Dissociation of dinitrogen on iron clusters: A detailed study of the Fe16 + N2 case.

Physical Chemistry Chemical Physics ◽

10.1039/d0cp05427e ◽

2020 ◽

Author(s):

Bole Chen ◽

Gennady L. Gutsev ◽

Weiguo Sun ◽

Xiao-Yu Kuang ◽

Cheng Lu ◽

...

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Basis Set ◽

Generalized Gradient ◽

Functional Theory ◽

Iron Clusters ◽

Generalized Gradient Approximation

The coalescence of two Fe8N as well as the structure of the Fe16N2 cluster were studied using density functional theory with the generalized gradient approximation and a basis set of...

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First principles calculations of structural, electronic and optical properties of InN compound

International Journal of Modern Physics B ◽

10.1142/s0217979215500289 ◽

2015 ◽

Vol 29 (05) ◽

pp. 1550028 ◽

Cited By ~ 4

Author(s):

R. Graine ◽

R. Chemam ◽

F. Z. Gasmi ◽

R. Nouri ◽

H. Meradji ◽

...

Keyword(s):

Optical Properties ◽

Band Structure ◽

Density Functional ◽

Local Density ◽

Indium Nitride ◽

Alternative Form ◽

Full Potential ◽

Generalized Gradient ◽

Pressure Derivative ◽

Electronic And Optical Properties

We carried out ab initio calculations of structural, electronic and optical properties of Indium nitride ( InN ) compound in both zinc blende and wurtzite phases, using the full-potential linearized augmented plane wave method (FP-LAPW), within the framework of density functional theory (DFT). For the exchange and correlation potential, local density approximation (LDA) and generalized gradient approximation (GGA) were used. Moreover, the alternative form of GGA proposed by Engel and Vosko (EV-GGA) and modified Becke–Johnson schemes (mBJ) were also applied for band structure calculations. Ground state properties such as lattice parameter, bulk modulus and its pressure derivative are calculated. Results obtained for band structure of these compounds have been compared with experimental results as well as other first principle computations. Our results show good agreement with the available data. The calculated band structure shows a direct band gap Γ → Γ. In the optical properties section, several optical quantities are investigated; in particular we have deduced the interband transitions from the imaginary part of the dielectric function.

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