scholarly journals C-2p Spin-Polarizations along with Two Mechanisms in Extended Carbon Multilayers: Insight from First Principles

2020 ◽  
Vol 5 (3) ◽  
pp. 48
Author(s):  
Samir F. Matar
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Magnetic Charge ◽  
The Other ◽  
Single Atom ◽  
Total Density ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Half Metallic ◽  
Total Density Of States

From density functional theory investigations helped with crystal chemistry rationale, single-atom C, embedded in layered hexagonal CC’n (n = 6, 12 and 18) networks, is stable in a magnetic state with M(C) = 2 μB. The examined compositions, all inscribed within the P6/mmm space group are characterized as increasingly cohesive with n, figuring mono-, bi- and tri-layered honeycomb-like C’6 networks respectively. The spin projected total density of states shows a closely half-metallic behavior with a gap at minority spins (↓) and metallic majority spins (↑). Such results together with the large C-C intersite separation and the integer 2 μB magnetization, let us propose an intra-band mechanism of magnetic moment onset on carbon 2p states. Support is provided from complementary calculations assuming a C2C’12 structure with planar 2C with d(C-C) = 2.46 Å resulting into a lowering of the magnetization down to the 0.985 μB/C atom and a ferromagnetic order arising from interband spin polarization on C where one nonbonding spin polarizes whereas the other is involved with the bonding with the other carbon. Illustration of proofs is provided with the magnetic charge density projected onto the different atoms, showing its prevalence around C, contrary to the C’n (C’6 layers), as well as electron localization function ELF.

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.

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.

DFT study of elastic, half-metallic and optical properties of Co2V(Al, Ge, Ga and Si) compounds

2017 ◽  
Vol 31 (14) ◽  
pp. 1750109 ◽  
Author(s):  
Heidar Khosravi ◽  
Arash Boochani ◽  
Golnaz Rasolian ◽  
Shahram Solaymani ◽  
Sirvan Naderi
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Magnetic Moments ◽  
Elastic Stability ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Spin Mode ◽  
Half Metallic ◽  
Lattice Constants ◽  
Optical Treatment

First-principles study of elastic, electronic and optical properties of full-Heusler Co2V(Al, Ge, Ga and Si) compounds are calculated through density functional theory (DFT) to obtain and compare the mentioned properties. Equilibrium lattice constants of these compounds are in good agreement with other works. Electronic calculations are shown full spin polarization at Fermi level for all compounds, so in the down spin, indirect bandgap is calculated as 0.33, 0.6, 0.2 and 0.8 eV for Co2V(Al, Ge, Ga and Si), respectively. The integer amounts of the magnetic moments are compatible with Slater–Pauling role. The optical treatment of Co2VGa is different from three other compounds. All mentioned compounds have metallic behavior by 22 eV plasmonic frequency. The imaginary part of the dielectric function for the up spin indicates that the main optical transitions occurred in this spin mode. Moreover, the elastic results show that the Co2VGa does not have elastic stability, but the other three compounds have fully elastic stability and the Co2V(Al, Ge and Si) belong to the hardness of materials.

scholarly journals HfS2 and TiS2 Monolayers with Adsorbed C, N, P Atoms: A First Principles Study

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 94
Author(s):  
Mailing Berwanger ◽  
Rajeev Ahuja ◽  
Paulo Cesar Piquini
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Molecular Species ◽  
First Principles ◽  
Density Functional ◽  
2D Materials ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Localized Levels

First principles density functional theory was used to study the energetic, structural, and electronic properties of HfS 2 and TiS 2 materials in their bulk, pristine monolayer, as well as in the monolayer structure with the adsorbed C, N, and P atoms. It is shown that the HfS 2 monolayer remains a semiconductor while TiS 2 changes from semiconductor to metallic behavior after the atomic adsorption. The interaction with the external atoms introduces localized levels inside the band gap of the pristine monolayers, significantly altering their electronic properties, with important consequences on the practical use of these materials in real devices. These results emphasize the importance of considering the interaction of these 2D materials with common external atomic or molecular species.

Pressure-Induced Tunable Magnetism and Half-Metallic Stability in Co2FeGa Heusler Alloy

2013 ◽  
Vol 477-478 ◽  
pp. 1303-1306
Author(s):  
Qin Xiang Gao
Keyword(s):  
Fermi Level ◽  
First Principles ◽  
Density Functional ◽  
High Energy ◽  
First Principles Calculations ◽  
Half Metallicity ◽  
Functional Theory ◽  
Half Metallic ◽  
Heusler Compound ◽  
The Density Functional Theory

Using the first-principles calculations within the density functional theory (DFT), we have investigated the structure, magnetism and half-metallic stability of Co2FeGa Heusler compound under pressure from 0 to 50GPa. The results revel that the lattice constant is gradually shrank and total magnetic moment in per unit slightly decreased with increasing pressure, respectively. Moreover, with the increase of the pressure, the Fermi level will move towards high-energy orientation. When the pressure reaches at 30GPa the most stable half-metallicity is observed which the Fermi level is located at the middle of the spin-minority gap.

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.

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.

A DFT study on the interaction between europium, uranium and SWCNT

Open Physics ◽  
2011 ◽  
Vol 9 (3) ◽  
Author(s):  
Ji-Chun Xie ◽  
Yong-Jian-Tang ◽  
Hong Zhang
Keyword(s):  
Band Structure ◽  
Valence Band ◽  
First Principles ◽  
Density Functional ◽  
Total Density ◽  
Density Of State ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Single Nucleus ◽  
The Eu

AbstractWe investigate the electronic and band structure for the (8; 0) single-wall carbon nanotube (SWCNT) with a europium (Eu) and a uranium (U) atom outside by using the first-principles method with the density functional theory (DFT). The calculated band structure (BS), total density of state (TDOS), and projected density of state (PDOS) can elucidate the differences between the pure (8; 0) SWCNT and the nuclei outside the SWCNT. The indirect band gaps are obtained when Eu and U atom are put outside the (8; 0) CNT; they are 0.037 eV and 0.036 eV, respectively, which is much smaller than 0.851 eV for pure CNT. Compared with pure (8; 0) SWCNT, the bottom of the conduction band moves down by 0.383 eV and 0.451 eV with the Eu and U outside, and the top of valence band moves up by 0.127 eV and 0.162 eV, respectively. More significantly, the top of the valence band has exceeded the fermi-level. So, a single nucleus changes the semiconductor character of pure nanotube to semi-metal.

scholarly journals The Effect of Indium Concentration on the Structure and Properties of Zirconium Based Intermetallics: First-Principles Calculations

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Fuda Guo ◽  
Junyan Wu ◽  
Shuai Liu ◽  
Yongzhong Zhan
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Indium Content ◽  
The Other ◽  
First Principles Calculation ◽  
First Principles Calculations ◽  
Structure And Properties ◽  
Functional Theory ◽  
Formation Enthalpies

The phase stability, mechanical, electronic, and thermodynamic properties of In-Zr compounds have been explored using the first-principles calculation based on density functional theory (DFT). The calculated formation enthalpies show that these compounds are all thermodynamically stable. Information on electronic structure indicates that they possess metallic characteristics and there is a common hybridization between In-p and Zr-d states near the Fermi level. Elastic properties have been taken into consideration. The calculated results on the ratio of the bulk to shear modulus (B/G) validate that InZr3has the strongest deformation resistance. The increase of indium content results in the breakout of a linear decrease of the bulk modulus and Young’s modulus. The calculated theoretical hardness ofα-In3Zr is higher than the other In-Zr compounds.

First-principles study of electronic transport and optical properties of penta-graphene, penta-SiC2 and penta-CN2

RSC Advances ◽  
2016 ◽  
Vol 6 (56) ◽  
pp. 50867-50873 ◽  
Author(s):  
Golibjon R. Berdiyorov ◽  
Mohamed El-Amine Madjet
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Electronic Transport ◽  
First Principles ◽  
Density Functional ◽  
Optoelectronic Properties ◽  
The Other ◽  
Functional Theory ◽  
First Principles Study

Optoelectronic properties of penta-graphene, penta-SiC2 and penta-CN2 are studied using density functional theory. Penta-SiC2 shows enhanced electronic transport and optical properties compared to the other systems.

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