scholarly journals The surface effect on the thermodynamic stability, half-metallic and optical properties of Co2MnGa(001) films: a DFT study

2019 ◽  
Vol 9 (4) ◽  
pp. 339-348
Author(s):  
R. Ashtari Faregh ◽  
A. Boochani ◽  
S. R. Masharian ◽  
F. H. Jafarpour
Keyword(s):  
Density Functional Theory ◽  
Thermodynamic Stability ◽  
Density Functional ◽  
Surface Effect ◽  
Optical Parameters ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Half Metallic ◽  
The Density Functional Theory ◽  
Full Heusler

Abstract In this study, the half-metallic properties, thermodynamic stability and optical parameters of the full-Heusler Co2MnGa compound and its four different terminations of Co–Co, Co–Mn, Mn–Ga and Co–Ga from the surface of Co2MnGa (001) have been calculated based on the density functional theory (DFT). The results confirm the ferromagnetic half-metallic behavior with a magnetic moment of 4.08 $$ \mu_{\text{B}} $$μB and a gap of 0.32 eV at the Fermi level of Co2MnGa bulk phase having a Cu2MnAl-type structure. The density of states curves showed that all possible terminations from the Co2MnGa (001) surface eliminate the half-metallic behavior except the termination of Mn–Ga case. Moreover, the results indicate that the termination of Mn–Ga with the lowest surface energy is the most stable termination for the application in spintronics. The optical coefficients such as real and imaginary dielectric function, refraction, extinction, energy loss function, optical conductivity and reflections of the bulk and Mn–Ga termination have been calculated and compared.

scholarly journals Первопринципное иследование полуметаллических свойств сплавов Гейслера Mn-=SUB=-2-=/SUB=-ScZ (Z=Al, Si, P, Ga, Ge, As, In, Sn, Sb)

2021 ◽  
Vol 63 (11) ◽  
pp. 1751
Author(s):  
Д.Р. Байгутлин ◽  
В.В. Соколовский ◽  
О.Н. Мирошкина ◽  
В.Д. Бучельников
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Heusler Alloys ◽  
Metallic State ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Half Metallic ◽  
Spintronic Devices ◽  
Exchange Correlation ◽  
The Density Functional Theory

The properties of Heusler alloys of the Mn2ScZ family (Z = Al, Si, P, Ga, Ge, As, In, Sn, Sb) are investigated within the framework of the density functional theory. The PBE GGA and meta-GGA SCAN functionals were used for approximation of the exchange-correlation interactions. Calculations show that PBE does not predict ideal half-metallic behavior, unlike SCAN. It is shown that at Z = P, Si, a transition from the half-metallic state to the metallic one is observed. This effect can be used to develop tunable spintronic devices.

An Investigation of Half-Metallic Ferromagnets Behavior in Hg2CuTi-Type Heusler Alloy Ti2FeAl by Using GGA

2012 ◽  
Vol 535-537 ◽  
pp. 1291-1294 ◽  
Author(s):  
Xiu De Yang ◽  
Bo Wu ◽  
Song Zhang
Keyword(s):  
Density Functional Theory ◽  
Heusler Alloy ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Half Metallic ◽  
Generalized Gradient Approximation ◽  
Indirect Exchange ◽  
The Density Functional Theory ◽  
Direct Hybridization

By using generalized gradient approximation (GGA) scheme within the density functional theory (DFT), the electronic and magnetic properties of Hg2CuTi-type Heusler alloy Ti2FeAl were investigated. The results reveal that a 100% spin polarization appears at Fermi level (εF) in Ti2FeAl, and is maintained during lattice range of 5.1Å~6.2Å. Ti2FeAl is one of stable Half-Metallic Ferromagnets (HMF) with a spin-minority gap of 0.5 eV at εF and total magnetic moment of 1μB per unit cell. Our studies also indicate that the competition between RKKY-type indirect exchange and direct hybridization of d-electronic atoms plays a dominating role in determining the magnetism.

scholarly journals Exploring half-metallic Co-based full Heusler alloys using a DFT+U method combined with linear response approach

RSC Advances ◽  
2019 ◽  
Vol 9 (52) ◽  
pp. 30462-30478 ◽  
Author(s):  
Kenji Nawa ◽  
Yoshio Miura
Keyword(s):  
Density Functional Theory ◽  
Electronic Structures ◽  
Linear Response ◽  
Density Functional ◽  
Heusler Alloys ◽  
Functional Theory ◽  
Half Metallic ◽  
Full Heusler ◽  
Full Heusler Alloys

A density functional theory (DFT)+U method based on linear response (LR) theory was applied to investigate the electronic structures of Co-based full Heusler alloys of ternary Co2YSi and quaternary Co2(Y,Mn)Si.

A Theoretical Study of Lithium-Doped Gallium Clusters by Density Functional Theory

2012 ◽  
Vol 67 (5) ◽  
pp. 289-295 ◽  
Author(s):  
Şükrü Şentürk ◽  
Yavuz Ekincioğlu
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Surface Effect ◽  
Geometrical Structures ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Lowest Unoccupied Molecular Orbital ◽  
The Stability ◽  
Average Bond ◽  
Homo Lumo

The geometrical structures, stabilities, and electronic properties of GanLi (n = 1 - 13) clusters were investigated within the density functional theory (DFT). The impurity lithium atom enhances the stability of GanLi (n = 1 - 13) clusters, especially GanLi (n = 9 - 13) compared to Gan(n = 9 - 14), that is at either apex position or side position. The dissociation energy, second-order energy differences, and the energy gaps between highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) indicate that the Ga7Li, Ga9Li, and Ga11Li clusters are more stable within the studied cluster range. Moreover, the variation of the average bond length of Ga-Li is due to the surface effect, and the binding strength increases resulting from the increase of charge amount.

Theoretical and Experimental Evaluation of the Effect of Fluorinated Substituent on the Topological Landscape and Thermodynamic Stability of Zeolitic Imidazolate Framework Polymorphs

2018 ◽  
Author(s):  
Mihails Arhangelskis ◽  
Athanassis Katsenis ◽  
Novendra Novendra ◽  
Zamirbek Akimbekov ◽  
Dayaker Gandrath ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Mechanochemical Synthesis ◽  
Thermodynamic Stability ◽  
Experimental Evaluation ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Zeolitic Imidazolate Framework ◽  
Functional Theory ◽  
Calorimetric Measurements ◽  
And Calorimetry

By combining mechanochemical synthesis and calorimetry with theoretical calculations, we demonstrate that dispersion-corrected periodic density functional theory (DFT) can accurately survey the topological landscape and predict relative energies of polymorphs for a previously inaccessible fluorine-substituted zeolitic imidazolate framework (ZIF). Experimental screening confirmed two out of three theoretically anticipated polymorphs, and the calorimetric measurements provided an excellent match to theoretically calculated energetic difference between them.<br>

scholarly journals Electron-phonon interaction in In-induced √7 ×√3 structures on Si(111) from first-principles

2021 ◽  
Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov
Keyword(s):  
Density Functional Theory ◽  
Double Layer ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Single Layer ◽  
Phonon Interaction ◽  
Functional Theory ◽  
Electron Phonon Interaction ◽  
The Density Functional Theory

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...

scholarly journals Study on the interaction between catechin and cholesterol by the density functional theory

2020 ◽  
Vol 18 (1) ◽  
pp. 357-368
Author(s):  
Kaiwen Zheng ◽  
Kai Guo ◽  
Jing Xu ◽  
Wei Liu ◽  
Junlang Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Density Functional ◽  
Antioxidant Properties ◽  
Micelle Formation ◽  
Aromatic Rings ◽  
Hydrogen Bond Interaction ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractCatechin – a natural polyphenol substance – has excellent antioxidant properties for the treatment of diseases, especially for cholesterol lowering. Catechin can reduce cholesterol content in micelles by forming insoluble precipitation with cholesterol, thereby reducing the absorption of cholesterol in the intestine. In this study, to better understand the molecular mechanism of catechin and cholesterol, we studied the interaction between typical catechins and cholesterol by the density functional theory. Results show that the adsorption energies between the four catechins and cholesterol are obviously stronger than that of cholesterol themselves, indicating that catechin has an advantage in reducing cholesterol micelle formation. Moreover, it is found that the molecular interactions of the complexes are mainly due to charge transfer of the aromatic rings of the catechins as well as the hydrogen bond interactions. Unlike the intuitive understanding of a complex formed by hydrogen bond interaction, which is positively correlated with the number of hydrogen bonds, the most stable complexes (epicatechin–cholesterol or epigallocatechin–cholesterol) have only one but stronger hydrogen bond, due to charge transfer of the aromatic rings of catechins.

A trinuclear chromium(III) chlorocarbyne

2021 ◽  
Author(s):  
Takashi Kurogi ◽  
Keiichi Irifune ◽  
Takahiro Enoki ◽  
Kazuhiko Takai
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Terminal Alkynes ◽  
Functional Theory ◽  
The Density Functional Theory

Reduction of CCl4 by CrCl2 in THF afforded a trinuclear chromium(III) carbyne [CrCl(thf)2)]3(μ3-CCl)(μ-Cl)3. The chlorocarbyne complex reacted with aldehydes to afford chloroallylic alcohols and terminal alkynes. The density functional theory...

scholarly journals Propiedades electrónicas y estructurales del Ga1-xCrxAs

2018 ◽  
Vol 42 (162) ◽  
pp. 26
Author(s):  
Nasly Y. Martínez Velásquez ◽  
Jairo Arbey Rodríguez Martínez
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Half Metallic ◽  
El Sistema ◽  
Quantum Espresso

Mediante el uso de principios basados en la teoría del funcional de la densidad - DFT (Density Functional Theory) se calcularon las propiedades electrónicas y estructurales del compuesto Ga1-xCrxAs. Empleando el método de ondas planas y la aproximación de pseudopotenciales atómicos ultra suaves se resolvieron las ecuaciones de Kohn-Sham. Para la energía de intercambio y correlación se empleó la aproximación de gradiente generalizado, dentro de la parametrización de Perdew-Burke-Ernzerhof (PBE) tal como está implementada en el código computacional Quantum-Espresso. Al dopar GaAs con impurezas de Cr, el sistema exhibe un comportamiento tipo half-metallic. Dicho material puede ser usado en espintrónica. © 2018. Acad. Colomb. Cienc. Ex. Fis. Nat.

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