Site Dependence of Electronic Structure of Gd Impurities in GaN

2011 ◽  
Vol 1290 ◽  
Author(s):  
Tawinan Cheiwchanchamnangij ◽  
Atchara Punya ◽  
Walter R. L. Lambrecht
Keyword(s):  
Electronic Structure ◽  
Magnetic Moments ◽  
Interstitial Site ◽  
Nitrogen Vacancy ◽  
Orbital Method ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Site Dependence ◽  
Structure Calculations ◽  
Energy Of Formation

ABSTRACTElectronic structure calculations are reported for Gd in GaN on Ga as well as on N site and for pairs of Gd on neighboring Ga and N sites, using the full-potential linearized muffin-tin orbital method in the local spin density approximation with Hubbard U corrections (LSDA+U). The energy of formation for the N site is found to be much higher than for the Ga site even after relaxations are included. The GdN configuration is found to be at best metastable (in ZB). In WZ and in the pair configurations, the Gd is found to move toward an interstitial site leaving a nitrogen vacancy behind. The electronic structure of these structures and their magnetic moments are discussed.

scholarly journals Program LMTART for electronic structure calculations

2005 ◽  
Vol 220 (5/6) ◽  
Author(s):  
Sergej Y. Savrasov
Keyword(s):  
Electronic Structure ◽  
Computer Program ◽  
Electronic Structure Calculations ◽  
Orbital Method ◽  
Full Potential ◽  
Structure Calculations ◽  
Linear Muffin Tin Orbital

AbstractA computer program LMTART for electronic structure calculations using full potential linear muffin-tin orbital method is described.

ELECTRONIC STRUCTURE AND MAGNETIC PROPERTIES OF Co2YZ(Y = Cr, Z = Al, Ga) TYPE HEUSLER COMPOUNDS: A FIRST PRINCIPLE STUDY

2012 ◽  
Vol 26 (08) ◽  
pp. 1250071 ◽  
Author(s):  
D. P. RAI ◽  
A. SHANKAR ◽  
SANDEEP ◽  
M. P. GHIMIRE ◽  
R. K. THAPA
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
Magnetic Moments ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Heusler Compounds ◽  
Generalized Gradient ◽  
Half Metallic ◽  
Augmented Plane Wave ◽  
3D Elements

The structural optimization was followed by the calculation of electronic structure and magnetic properties on Co 2 CrAl and Co 2 CrGa . The structure optimization was based on generalized gradient approximation (GGA). The calculation of electronic structure was based on full potential linear augmented plane wave (FPLAPW) method within local spin density approximation (LSDA). We studied the electronic structure and magnetic properties. Results of density of states (DOS) and band structures shows that Co 2 CrAl and Co 2 CrGa are half-metallic ferromagnets (HMFS). The calculated magnetic moments of Co 2 CrAl and Co 2 CrGa are 2.915 and 3.075 μ B , respectively. We have calculated the onsite d–d coulomb and exchange interaction (U) For 3d elements like Co and Cr . The strongly localized d states were treated with LSDA+U method.

ELECTRONIC STRUCTURE OF SOLIDS IN THE SELF-INTERACTION CORRECTED LOCAL-SPIN-DENSITY APPROXIMATION

1993 ◽  
Vol 04 (02) ◽  
pp. 417-424
Author(s):  
AXEL SVANE
Keyword(s):  
Electronic Structure ◽  
Spin Density ◽  
Tight Binding ◽  
Energy Functional ◽  
Descent Method ◽  
Steepest Descent Method ◽  
Orbital Method ◽  
Local Spin Density Approximation ◽  
Local Spin ◽  
Structure Calculations

An ab-initio implementation of self-interaction corrections (SIC) within local spin density (LSD) electronic structure calculations of solids is presented. The linear-muffin-tin orbital method is used in the tight-binding representation and with the atomic spheres approximation. The variational minimum of the SIC-LSD energy functional is found by the steepest descent method, i.e., no matrix diagonalizations are involved. Special care is taken to secure stability with respect to unitarian mixing of electron states. Applied to the transition metal monoxides and La 2 CuO 4 the SIC-LSD significantly improves the desription in comparison to LSD.

ELASTIC PROPERTIES OF STRAINED FCC AND HCP IRON

1993 ◽  
Vol 07 (01n03) ◽  
pp. 207-211
Author(s):  
T. KRAFT ◽  
M. METHFESSEL ◽  
M. VAN SCHILFGAARDE ◽  
M. SCHEFFLER
Keyword(s):  
Energy Cost ◽  
Interplanar Distance ◽  
Orbital Method ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Nearest Neighbour ◽  
Density Approximation ◽  
Neighbour Distance ◽  
Large Lattice ◽  
Fcc Phase

Using the full-potential linear muffin-tin orbital method within the local spin-density approximation we analyse the influence of the nearest neighbour distance on fcc(111) or hcp(0001) iron layers. The LDA-LSDA error in describing ferromagnetic phases is determined to be at least 15 mRy/atom. As a consequence of this error, our calculations favour paramagnetic ground states. In this sense, the reported results have some model character. However, our analysis of the elastic energy cost under distortions should hold for transition metals in general. Allowing relaxations of the interplanar distance the fcc phase can become energetically favourable over the hcp phase at large lattice mismatches. The main reason for this behaviour is the enhanced stiffness of the hcp interplanar bonds due to the shortening of the axial c/a ratio.

Effect of Boron and Hydrogen on the Electronic Structure of Ni3Al

1993 ◽  
Vol 319 ◽  
Author(s):  
N. Kioussis ◽  
H. Watanabe ◽  
R.G. Hemker ◽  
W. Gourdin ◽  
A. Gonis ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Charge Density ◽  
First Principles ◽  
Electronic Structure Calculations ◽  
Interstitial Site ◽  
Octahedral Interstitial Site ◽  
Interstitial Region ◽  
Ordered Intermetallic ◽  
Lmto Method ◽  
Structure Calculations

AbstractUsing first-principles electronic structure calculations based on the Linear-Muffin-Tin Orbital (LMTO) method, we have investigated the effects of interstitial boron and hydrogen on the electronic structure of the L12 ordered intermetallic Ni3A1. When it occupies an octahedral interstitial site entirely coordinated by six Ni atoms, we find that boron enhances the charge distribution found in the strongly-bound “pure” Ni3AI crystal: Charge is depleted at Ni and Al sites and enhanced in interstitial region. Substitution of Al atoms for two of the Ni atoms coordinating the boron, however, reduces the interstitial charge density between certain atomic planes. In contrast to boron, hydrogen appears to deplete the interstitial charge, even when fully coordinated by Ni atoms. We suggest that these results are broadly consistent with the notion of boron as a cohesion enhancer and hydrogen as an embrittler.

Half-metallic ferromagnetism in V-doped ZnTe semiconductor at reduced dopant concentration

2014 ◽  
Vol 28 (13) ◽  
pp. 1450104 ◽  
Author(s):  
M. Sajjad ◽  
H. X. Zhang ◽  
N. A. Noor ◽  
S. M. Alay-e-Abbas ◽  
M. Abid ◽  
...  
Keyword(s):  
Density Functional ◽  
Spin Exchange ◽  
Density Functional Theory Calculations ◽  
Orbital Method ◽  
Ferromagnetic Behavior ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Generalized Gradient ◽  
Half Metallic ◽  
Bonding Properties

In this study, we examine the structural, electronic, magnetic and bonding properties of zincblende phase Zn 1-x V x Te (x = 0.0625, 0.125, 0.25) compounds to present them as suitable candidates for spintronic applications. Density functional theory calculations have been used by implementing the accurate full-potential linear-augmented-planewave plus local-orbital method. Structural properties have been computed using Wu–Cohen generalized gradient approximation, whereas the modified Becke and Johnson local (spin) density approximation (mBJLDA) function has been employed for the evaluating ground state electronic properties and ferromagnetic behavior. The half-metallic (HM) ferromagnetism in Zn 1-x V x Te is analyzed in terms of V -3d states and it is shown that mBJLDA predicts wide HM gaps which promise the possibility of achieving V -doped ZnTe with high Curie temperature. The spin exchange splittings Δx(d) and Δx(pd) have been estimated and the contribution of conduction band (CB) and valence band (VB) in exchange splitting is calculated in terms of the exchange constants N0α and N0β. Furthermore, spin-polarized charge density calculation is presented for elucidating the bonding nature, while pressure dependence of total magnetic moment for three concentrations of V -doped ZnTe is also discussed.

Low Energy K-Dependent Electronic Structure of the Layered Magnetoresistive Oxide La1.2Sr1.8Mn2O7

1997 ◽  
Vol 494 ◽  
Author(s):  
T. Saitoh ◽  
D. S. Dessau ◽  
C.-H. Park ◽  
Z.-X. Shen ◽  
P. Villella ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Current System ◽  
Coupling Model ◽  
Local Spin Density Approximation ◽  
Energy Bands ◽  
Strong Electron ◽  
Colossal Magnetoresistive ◽  
Band Structure Calculations ◽  
Structure Calculations

ABSTRACTWe have studied the fc-dependent electronic structure of the layered colossal magnetoresistive manganite La1.2Sr1.8Mn2O7 using high-resolution angle-resolved photoemission spectroscopy. We found dispersive energy bands as a function of the crystal momentum k near the Fermi level (EF). We have also performed local spin density approximation (LSDA)+U band-structure calculations on the current system. The overall experimental dispersion relation is basically in agreement with the band-structure calculations yet close to EF there is a significant deviation from the predicted dispersions. Instead of clear Fermi-surface (FS) crossings, we observe a depression of the features as the FS is approached as if there is a “pseudo” gap in the excitation spectrum. The pseudogap continuously opens with temperature and does not show further significant opening above Tc, corresponding to the metal-insulator transition. Those unusual aspects of the spectra has been discussed from the viewpoint of the strong electron-lattice coupling model.

TRANSFORMATION OF THE ELECTRONIC STRUCTURE OF Cu INTO Cu2O IN THE ADSORPTION OF OXYGEN

1999 ◽  
Vol 06 (03n04) ◽  
pp. 383-388 ◽  
Author(s):  
V. P. BELASH ◽  
I. N. KLIMOVA ◽  
V. I. KORMILETS ◽  
V. YU. TRUBITSIN ◽  
L. D. FINKELSTEIN
Keyword(s):  
Electronic Structure ◽  
Photoelectron Spectroscopy ◽  
Surface Oxidation ◽  
Oxygen Adsorption ◽  
Copper Surface ◽  
Photoelectron Spectra ◽  
Orbital Method ◽  
Full Potential ◽  
Wide Range ◽  
Pure Cu

Systematic photoelectron-spectroscopy studies of the oxygen adsorption on a polycrystalline copper in a wide range of oxygen exposures allowed us to trace the step-by-step transformation of the electronic structure of pure Cu into the electronic structure of Cu 2 O . With the use of the density-of-states calculations implemented by the full-potential linear muffin-tin-orbital method, the interpretation of a number of features in the photoelectron spectra and their behavior with the increase of oxygen exposure was carried out. It was also shown that copper-surface oxidation proceeds in three main steps.

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