First-Principles Calculations of the Structure and Magnetic Phases of FeAs2 Compound under Pressure

Understanding of different magnetic configurations for the FeAs2 iron pnictide compound is carried out using first-principles studies based on spin density functional theory (DFT) within the generalized gradient approximation (GGA), including the spin–orbit coupling (SOC). The calculated stable phase is in the marcasite (Pnnm) with nonmagnetic spin-ordering. We find that the FeAs2 compound in the nonmagnetic (NM) marcasite phase undergoes pressure-induced phase transition to the antiferromagnetic (AFM1) marcasite phase at 12[Formula: see text]GPa, then to the AFM CuAl2 ([Formula: see text]4/mcm) phase at 63[Formula: see text]GPa. The phase transition is also accompanied by semiconducting (marcasite phase) to metallic (CuAl2 phase) transition. The calculated electronic density of states profile shows the hybridization of the Fe-3[Formula: see text] and As-4[Formula: see text] orbitals plays an important role in determining the electronic and magnetic characters of this compound. The associated phase transition results in increased Fe-3d orbitals around the Fermi energy level.

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First-principles calculations of structural and electronics properties of YInN alloy

DYNA ◽

10.15446/dyna.v88n217.88374 ◽

2021 ◽

Vol 88 (217) ◽

pp. 50-57

Author(s):

Gladys Patricia Abdel Rahim Garzón ◽

Jairo Arbey Rodriguez Martinez ◽

María Guadalupe Moreno Armenta ◽

Miguel Espitia Rico

Keyword(s):

Phase Transition ◽

Density Functional Theory ◽

First Principles ◽

Density Functional ◽

Stable Phase ◽

First Principles Calculations ◽

Functional Theory ◽

Technical Data ◽

Structural And Electronic Properties ◽

Semiconductor Behavior

We study the structural and electronic properties of YxIn1-xN in the concentrations x = 0, ¼, ½, ¾, and 1 in the B1, B2, B3 and B4 structures using density functional theory (DFT). The calculations show that for Y0.75In0.25N, the B1 structure is the most favorable energetically. It was determined that between in the supercell, the most energetically stable structure is the B3 phase. Additionally, between concentrations x of Yttrium, the compound is most energetically favorable in the B4 phase. Technical data that are in agreement were recently reported by other authors. Finally, between 0.12 , the most stable phase is B1. Additionally, there is no phase transition between the four structures considered. The DOS and band structure show that Y0.75In0.25N in the B1 and B3 phases exhibits semiconductor behavior, with a direct gap of ~0.6 eV and ~0.7 eV, respectively while Y0.75In0.25N in the B4 phase has an indirect one of ~0.8 eV.

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Electronic structure of cubic BaTbO3 from first-principles pseudopotential calculations

Canadian Journal of Physics ◽

10.1139/p06-008 ◽

2006 ◽

Vol 84 (2) ◽

pp. 115-120 ◽

Cited By ~ 3

Author(s):

G Y Gao ◽

K L Yao ◽

Z L Liu

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Exchange Correlation ◽

Pseudopotential Calculations ◽

Correlation Potential ◽

Density Contour

First-principles calculations of the electronic structure are performed for cubic BaTbO3 using the plane-wave pseudopotential method within the framework of density functional theory and using the generalized gradient approximation for the exchange-correlation potential. Our calculations show that cubic BaTbO3 is metallic, and that this metallic character is mainly governed by the Tb 4f electrons and the hybridization between the Tb 5d and O 2p states. From the analysis of the density of states, band structure, and charge density contour, we find that the chemical bonding between Tb and O is covalent while that between Ba and TbO3 is ionic. PACS Nos.: 71.15.Mb, 71.20.-b

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Barrier to Migration of the Intrinsic Defects in Silicon in Different Charged System Using First-principles Calculations

MRS Proceedings ◽

10.1557/proc-864-e9.17 ◽

2005 ◽

Vol 864 ◽

Cited By ~ 1

Author(s):

Jinyu Zhang

Keyword(s):

Density Functional Theory ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Diffusion Behavior ◽

Generalized Gradient Approximation ◽

Charged System ◽

And Diffusion

AbstractUsing density functional theory (DFT) calculations within the generalized gradient approximation (GGA), we have investigated the structure, energies and diffusion behavior of Si defects including interstitial, vacancy, FFCD and divacancy in various charged states.

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Quantum-chemical study of nitrogen and magnesium co-doping in α-Cr2O3

Modern Physics Letters B ◽

10.1142/s0217984916502195 ◽

2016 ◽

Vol 30 (14) ◽

pp. 1650219

Author(s):

Soraya Jácome ◽

Arvids Stashans

Keyword(s):

First Principles ◽

Density Functional ◽

Quantum Chemical Study ◽

Chemical Study ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Text Type ◽

Co Doping ◽

The Density Functional Theory

Study of corundum-type chromium oxide ([Formula: see text]-Cr2O3) crystal doped with the nitrogen and magnesium impurities has been carried out through the use of first-principles calculations based on the density functional theory (DFT) and generalized gradient approximation (GGA). Three cases corresponding different impurity–impurity distances have been considered. Structural, electronic and magnetic properties have been studied for all co-doping cases. The [Formula: see text]-type electrical conductivity was found when distance between the Mg and N atoms is equal to 4.10 Å. The results obtained are consistent with the available experimental data.

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PHASE TRANSITION, ELASTIC AND THERMODYNAMIC PROPERTIES OF BERYLLIUM VIA FIRST PRINCIPLES

International Journal of Modern Physics B ◽

10.1142/s0217979213501300 ◽

2013 ◽

Vol 27 (24) ◽

pp. 1350130 ◽

Cited By ~ 3

Author(s):

YAN CHENG ◽

HAI-HUA CHEN ◽

FAN-XIANG XUE ◽

GUANG-FU JI ◽

MIN GONG

Keyword(s):

Phase Transition ◽

Thermodynamic Properties ◽

First Principles ◽

Density Functional ◽

High Pressures ◽

Intermediate Phase ◽

Linear Thermal Expansion ◽

Generalized Gradient ◽

Functional Theory ◽

Bcc Phase

The phase transition, elastic and thermodynamic properties of beryllium (Be) have been studied at high pressures by plane-wave ultrasoft pseudopotential density functional theory (DFT) within the generalized gradient approximation (GGA). It is found that the hcp → bcc phase transition of Be occurs at 506 GPa (T = 0 K ) and occurs at 1200 K (P = 0 GPa ). The coefficients of linear thermal expansion of the hexagmal close-packed (hcp), bcc and orthorhombic Be have been calculated. The hcp → orthorhombic → bcc phase transitions do not occur in all range of pressures, that is to say, the orthorhombic Be is not an intermediate phase between the hcp and bcc Be. The obtained bulk modulus (B0) are 113.2 GPa (for hcp Be), 113.1 GPa (for bcc Be) and 70.5 GPa (for orthorhombic Be), respectively.

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Electronic structure and elastic properties of AgZn under pressure from first-principles calculations

Canadian Journal of Physics ◽

10.1139/cjp-2015-0684 ◽

2016 ◽

Vol 94 (3) ◽

pp. 328-333

Author(s):

Yasemin Ö. Çiftci

Keyword(s):

Density Of States ◽

First Principles ◽

Density Functional ◽

Elastic Stiffness ◽

Distribution Analysis ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

B2 Structure ◽

Bonding Characteristic

In this study, the structural, elastic, electronic, and bonding nature of AgZn in B2 structure under pressure have been investigated by performing first principles calculations using density functional theory. The exchange-correlation potentials were treated within the generalized gradient approximation. The calculated quantities agree well with the available results. The electronic properties, such as band structure and density of states reveal that AgZn is metallic in nature with a large overlap at the Fermi level. The single-crystal elastic stiffness constants of AgZn are investigated using the stress–strain method. Present results for elastic constants show that AgZn is mechanically stable. The chemical bonding is interpreted by calculating the density of states and electron density distribution analysis. AgZn has ionic bonding characteristic.

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THERMAL PROPERTIES OF THE XB2(X = Ag, Au) COMPOUNDS: A FIRST-PRINCIPLES STUDY

International Journal of Modern Physics B ◽

10.1142/s021797921350046x ◽

2013 ◽

Vol 27 (12) ◽

pp. 1350046

Author(s):

HAVVA BOGAZ OZISIK ◽

KEMAL COLAKOGLU ◽

ENGIN DELIGOZ

Keyword(s):

Density Functional Theory ◽

First Principles ◽

Density Functional ◽

Debye Model ◽

First Principles Calculations ◽

Correlation Effects ◽

Generalized Gradient ◽

Functional Theory ◽

Exchange Correlation ◽

Generalized Gradient Approximation

The thermodynamic properties of AgB 2 and AuB 2 compounds in AlB 2 and OsB 2-type structures are investigated from first-principles calculations based on density functional theory (DFT) using projector augmented waves (PAW) potentials within the generalized gradient approximation (GGA) for modeling exchange-correlation effects, respectively. Specifically, using the quasi-harmonic Debye model, the effects of pressure and temperature, up to 100 GPa and 1400 K, on the bulk modulus, Debye temperature, thermal expansion, heat capacity and the Grüneisen parameter are calculated successfully and trends are discussed.

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Structural Phase Transition and Electronic Properties of MgCe under High Pressure from First-Principles Calculations

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.577.102 ◽

2014 ◽

Vol 577 ◽

pp. 102-107

Author(s):

Qiu Xiang Liu ◽

De Ping Lu ◽

Rui Jun Zhang ◽

Lei Lu ◽

Shi Fang Xie

Keyword(s):

Phase Transition ◽

Ground State ◽

First Principles ◽

Electronic Structures ◽

Density Functional ◽

High Pressures ◽

Local Density ◽

Structural Phase ◽

First Principles Calculations ◽

Functional Theory

The structural stability of MgCe under high pressures has been investigated by using the first-principles plane-wave pseudopotential density functional theory within the local density approximation (LDA). The obtained results predict that MgCe in the Ba structure is predicted to be the most stable structure corresponding to the ground state, because of lowest total energy. MgCe undergoes a pressure-induced phase transition from the Ba structure to B32 structure at 36 GPa. And no further transition is found up to 120 GPa. In addition, the electronic structures of four structures of MgCe are also calculated and discussed.

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

10.21203/rs.3.rs-467643/v1 ◽

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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First-Principles Calculations of the Electronic Structure and Optical Properties of Yttrium-Doped ZnO Monolayer with Vacancy

Materials ◽

10.3390/ma13030724 ◽

2020 ◽

Vol 13 (3) ◽

pp. 724

Author(s):

Qian Wu ◽

Ping Wang ◽

Yan Liu ◽

Han Yang ◽

Jingsi Cheng ◽

...

Keyword(s):

Oxygen Vacancy ◽

First Principles ◽

Density Functional ◽

Density Functional Theory Calculations ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Light Region ◽

Application Potential ◽

Doped Zno

The electronic structures and optical characteristics of yttrium (Y)-doped ZnO monolayers (MLs) with vacancy (zinc vacancy, oxygen vacancy) were investigated by the first-principles density functional theory. Calculations were performed with the GGA+U (generalized gradient approximation plus U) approach, which can accurately estimate the energy of strong correlation semiconductors. The results show that the formation energy values of Y-doped ZnO MLs with zinc or oxygen vacancy (VZn, VO) are positive, implying that the systems are unstable. The bandgap of Y-VZn-ZnO was 3.23 eV, whereas that of Y-VO-ZnO was 2.24 eV, which are smaller than the bandgaps of pure ZnO ML and Y-doped ZnO MLs with or without VO. Impurity levels appeared in the forbidden band of ZnO MLs with Y and vacancy. Furthermore, Y-VZn-ZnO will result in a red-shift of the absorption edge. Compared with the pure ZnO ML, ZnO MLs with one defect (Y, VZn or VO), and Y-VZn-ZnO, the absorption coefficient of Y-VO-ZnO was significantly enhanced in the visible light region. These findings demonstrate that Y-VO-ZnO would have great application potential in photocatalysis.

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