Ground State Properties And Magnetism In Substitutionally Disordered Fe1-xCrx Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
W. A. Shelton ◽  
F. J. Pinski ◽  
D. D. Johnson ◽  
D. M. Nicholson ◽  
G. M. Stocks
Keyword(s):  
Ground State ◽  
First Principles ◽  
Correlation Energy ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
Potential Approximation ◽  
Spin Polarized ◽  
Self Consistent ◽  
Cr Concentration ◽  
The Individual

AbstractWe have performed calculations of the electronic structure of the random substitutional bcc Fe1-xCrx alloys, using the spin-polarized, self-consistent Korringa, Kohn and Rostoker coherent potential approximation (KKR-CPA) method. This is a first principles method based on a local spin density approximation for electron exchange and correlation energy. For the iron-rich alloys, we find that the average moment decreases linearly with Cr concentration, although the individual moments show a different concentration dependence and the Cr moment is anti-parallel to the Fe moment. This system is similar to Fe1-xVx system, although some details are different.

A first principles investigation of the electronic structure of actinide oxides

2010 ◽  
Vol 1265 ◽  
Author(s):  
Leon Petit ◽  
Axel Svane ◽  
Zdzislawa Szotek ◽  
Walter Temmerman ◽  
Malcolm Stocks
Keyword(s):  
Ground State ◽  
First Principles ◽  
Electronic Structures ◽  
The Self ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
First Principles Calculations ◽  
Oxidation Number ◽  
Actinide Oxides ◽  
Ionic Nature

AbstractThe ground state electronic structures of the actinide oxides AO, A2O3 and AO2 (A=U, Np, Pu, Am, Cm, Bk, Cf) are determined from first-principles calculations using the self-interaction corrected local spin-density approximation. Our study reveals a strong link between preferred oxidation number and degree of localization. The ionic nature of the actinide oxides emerges from the fact that those oxides where the ground state is calculated to be metallic do not exist in nature, as the corresponding delocalized f-states favour the accommodation of additional O atoms into the crystal lattice.

scholarly journals Accurate spin-dependent electron liquid correlation energies for local spin density calculations: a critical analysis

1980 ◽  
Vol 58 (8) ◽  
pp. 1200-1211 ◽  
Author(s):  
S. H. Vosko ◽  
L. Wilk ◽  
M. Nusair
Keyword(s):  
Spin Density ◽  
Correlation Energy ◽  
Electron Gas ◽  
Interpolation Formula ◽  
Maximum Error ◽  
Energy Functional ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
Local Spin ◽  
Spin Polarized

We assess various approximate forms for the correlation energy per particle of the spin-polarized homogeneous electron gas that have frequently been used in applications of the local spin density approximation to the exchange-correlation energy functional. By accurately recalculating the RPA correlation energy as a function of electron density and spin polarization we demonstrate the inadequacies of the usual approximation for interpolating between the para- and ferro-magnetic states and present an accurate new interpolation formula. A Padé approximant technique is used to accurately interpolate the recent Monte Carlo results (para and ferro) of Ceperley and Alder into the important range of densities for atoms, molecules, and metals. These results can be combined with the RPA spin-dependence so as to produce a correlation energy for a spin-polarized homogeneous electron gas with an estimated maximum error of 1 mRy and thus should reliably determine the magnitude of non-local corrections to the local spin density approximation in real systems.

GROUND-STATE PROPERTIES OF Mn2 AND Fe2 IN THE LOCAI-SPIN-DENSITY APPROXIMATION

1993 ◽  
Vol 07 (01n03) ◽  
pp. 560-563 ◽  
Author(s):  
J. PIECHOTA ◽  
M. SUFFCZYŃSKI
Keyword(s):  
Spin Density ◽  
Ground State ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
Equilibrium Distance ◽  
Ground State Properties ◽  
Spin Polarized ◽  
Antiferromagnetic Ground State ◽  
Symmetry Constraints ◽  
Full Symmetry

Ab initio self-consistent all-electron spin-polarized calculations have been performed for the ground-state properties of the Mn 2 and Fe 2 molecules using the local-spin-density approximation. The total energy, the binding energy, the equilibrium distance, vibrational frequency, and the ground-state configuration are reported for each of these dimers. While for Fe 2 the region near equilibrium distance, r e , is characterized by full-symmetry (D∞ h ) molecular orbitals, for Mn 2 the symmetry breaking is essential: The true, "antiferromagnetic", ground state can be obtained only if reduced, C∞ v , symmetry constraints are used. These results are compared with other calculations and experimental results, where available.

scholarly journals Geometries and Electronic States of Divacancy Defect in Finite-Size Hexagonal Graphene Flakes

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Lili Liu ◽  
Shimou Chen
Keyword(s):  
Ground State ◽  
First Principles ◽  
Density Functional ◽  
Singlet State ◽  
Tight Binding ◽  
Finite Size ◽  
Electronic States ◽  
Closed Shell ◽  
Graphene Flakes ◽  
Self Consistent

The geometries and electronic properties of divacancies with two kinds of structures were investigated by the first-principles (U) B3LYP/STO-3G and self-consistent-charge density-functional tight-binding (SCC-DFTB) method. Different from the reported understanding of these properties of divacancy in graphene and carbon nanotubes, it was found that the ground state of the divacancy with 585 configurations is closed shell singlet state and much more stable than the 555777 configurations in the smaller graphene flakes, which is preferred to triplet state. But when the sizes of the graphene become larger, the 555777 defects will be more stable. In addition, the spin density properties of the both configurations are studied in this paper.

SIC-LSD study of δ-Pu and PuO2±x

2003 ◽  
Vol 802 ◽  
Author(s):  
L. Petit ◽  
A. Svane ◽  
Z. Szotek ◽  
W. M. Temmerman
Keyword(s):  
Spin Density ◽  
Ground State ◽  
Electronic Structures ◽  
The Self ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
Ground State Configuration ◽  
Local Spin ◽  
Δ Phase ◽  
State Configuration

ABSTRACTThe electronic structures of actinide solid systems are calculated using the self-interaction corrected local spin density approximation. Within this scheme the 5f electron manifold is considered to consist of both localized and delo-calized states, and by varying their relative proportions the energetically most favourable (ground state) configuration can be established. Specifically, we discuss elemental Pu in its δ-phase, and the effects of adding O to PuO2.

Ab initio calculations of the magnetic properties of TM (Ti, V)-doped zinc-blende ZnO

2018 ◽  
Vol 32 (03) ◽  
pp. 1850025 ◽  
Author(s):  
F. Goumrhar ◽  
L. Bahmad ◽  
O. Mounkachi ◽  
A. Benyoussef
Keyword(s):  
Magnetic Properties ◽  
First Principles ◽  
Exchange Coupling ◽  
Local Density ◽  
Density Approximation ◽  
Potential Approximation ◽  
Half Metallic ◽  
Suitable Material ◽  
Zinc Blende ◽  
Exchange Coupling Interaction

In order to promote suitable material to be used in spintronics devices, this study purposes to evaluate the magnetic properties of the titanium and vanadium-doped zinc-blende ZnO from first-principles. The calculations of these properties are based on the Korringa–Kohn–Rostoker (KKR) method combined with the coherent potential approximation (CPA), using the local density approximation (LDA). We have calculated and discussed the density of states (DOSs) in the energy phase diagrams for different concentration values, of the dopants. We have also investigated the magnetic and half-metallic properties of this doped compound. Additionally, we showed the mechanism of the exchange coupling interaction. Finally, we estimated and studied the Curie temperature for different concentrations.

Electronic Structure Study of Ni/Al2O3/Ni from First-Principles

2007 ◽  
Vol 336-338 ◽  
pp. 2540-2542
Author(s):  
Jia Xiang Shang ◽  
Meng Qiu Guo
Keyword(s):  
Electronic Structure ◽  
Spin Polarization ◽  
First Principles ◽  
Tunnel Junctions ◽  
Structure Study ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
Absolute Value ◽  
Interface Models ◽  
Discrete Variational Method

The electronic structure and magnetic properties of Ni/Al2O3/Ni tunnel junctions with O-terminated and Al-terminated interface models are investigated by first-principles discrete variational method with the local-spin-density approximation. The results show that the interface atomic has an important effect on interface electronic state and spin polarization as well as TMR ratio. For the O-terminated and Al-terminated interface models, spin polarization at Fermi level of Ni layers exhibit negative. It is found that absolute value of spin polarization as well as TMR ratio of Al-terminated interface models is much larger than that of O-terminated interface, which shows over-oxidization of Al layer could deteriorate magnetoresistance properties.

FIRST-PRINCIPLES STUDY OF MAGNETISM AND DEFECT STATE PROPERTIES OF ANTIPEROVSKITE GaC1-xMn3

2010 ◽  
Vol 24 (10) ◽  
pp. 953-962 ◽  
Author(s):  
L. HUA ◽  
L. WANG ◽  
L. F. CHEN
Keyword(s):  
Ground State ◽  
First Principles ◽  
Density Functional ◽  
Unit Cell Volume ◽  
Magnetic Transition ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Spin Polarized ◽  
Volume Decrease

We have investigated the electronic and magnetic properties of GaC 1-x Mn 3 (x = 0, 0.125, 0.25) using first-principles density functional theory within the generalized gradient approximation (GGA) + U schemes. The crystal structures of the compounds are cubic for x = 0, 0.125, 0.25. The lattice parameters and unit cell volume decrease as the C vacancy increase. Our spin polarized calculations give metallic ground state for x = 0, 0.125, 0.25. The magnetic structure for x = 0, 0.125 are antiferromagnetic, while for x = 0.25 it is ferromagnetic. From the density of states (DOS), the hybridization between the C 2p and Mn 3d state is the main reason for magnetic transition.

DIFFUSION MONTE CARLO STUDY OF GROUND STATE PROPERTIES OF QUANTUM DOTS

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1443-1446 ◽  
Author(s):  
FRANCESCO PEDERIVA
Keyword(s):  
Quantum Dots ◽  
Monte Carlo ◽  
Ground State ◽  
Monte Carlo Study ◽  
Wave Functions ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
Diffusion Monte Carlo ◽  
Hartree Fock ◽  
Parabolic Quantum Dot

We present the results of Diffusion Monte Carlo (DMC) calculations based on accurate multiconfiguration wave functions for N electrons (N≤13) confined to a parabolic quantum dot. The density and correlation energies have been computed and compared with the predictions of local spin density approximation theory (LSDA). We also computed the addition energy a function of the number of electrons in the dot, and compared them with the results of LSDA and Hartree Fock calculations. DMC results show a behavior qualitatively closer to the result of recent capacitance experiments.

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