Magnetism of Zn0.75Cr0.25S with ordered doping configurations predicted by generalized gradient approximation plus Hubbard U

2011 ◽  
Vol 109 (8) ◽  
pp. 083925 ◽  
Author(s):  
Lang Sun ◽  
Guangshe Li ◽  
Xiangfeng Guan ◽  
Liping Li ◽  
Liming Wu
Keyword(s):  
Generalized Gradient ◽  
Generalized Gradient Approximation ◽  
Hubbard U

Effect of Replacement of Fe2+ by Co2+ in W-Type Hexagonal Ferrite BaFe18O27 to its Electronic Properties from First Principles

2012 ◽  
Vol 424-425 ◽  
pp. 137-140
Author(s):  
Chung Ho Ri ◽  
Lin Li ◽  
Yang Qi ◽  
Su Nam Kim
Keyword(s):  
First Principles ◽  
Carrier Density ◽  
Mixed Valence ◽  
Charge Carrier Density ◽  
Generalized Gradient ◽  
Ground Structure ◽  
Generalized Gradient Approximation ◽  
Valence States ◽  
Hubbard U ◽  
Electronic Ground

Using a model in which Fe at 6g sites is assumed to be partially replaced by Co, the electronic ground structure of BaCo2Fe16O27and the origin of the electrical conductivity have been studied within framework of the generalized gradient approximation (GGA) plus Hubbard U (GGA+U) calculation. Replacement of Fe at 6g site of BaFe18O27by Co causes the mixed valence states of Fe cations at 6g sites to vanish and the charge carrier density to lower. This is the main reason why both of materials reveal high electrical conductive anisotropy and the electrical resistivity of BaCo2-W is 103~104times higher than BaFe2-W.

GEOMETRY OF DOPAMINE ADSORPTION ON RUTILE (110) SURFACE

2014 ◽  
Vol 28 (10) ◽  
pp. 1450071 ◽  
Author(s):  
DARWIN CASTILLO ◽  
JORGE ONTANEDA ◽  
ARVIDS STASHANS
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Generalized Gradient ◽  
Surface Geometry ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Hubbard U ◽  
Adsorption Geometry ◽  
Gap Width ◽  
Band Gap Width

Density functional theory (DFT) and generalized gradient approximation (GGA) have been employed to study adsorption geometry and electronic properties of the system consisting of rutile (110) surface and dopamine molecule. Hubbard U-like term is included to consider more adequately 3d electrons of Ti atoms. Results indicate that dopamine adsorption takes place in a bidentate geometry by forming strong bonds between two molecular oxygens and two titaniums situated on the surface. Geometry changes of molecular atoms, as well as those constituting upmost layer of the surface has been discussed in detail. Reduction in the band-gap width due to the adsorption has been found implying potential interest of the system for light-harvesting solar cells.

Interstitial vs. Substitutional Metal Insertion in V2O5 as Post-Lithium Ion Battery Cathode: A Comparative GGA/GGA+U Study with Localized Bases

2020 ◽  
Author(s):  
Daniel Koch ◽  
Sergei Manzhos
Keyword(s):  
Electronic Structure ◽  
Plane Wave ◽  
Transition Metal Oxides ◽  
Reasonable Agreement ◽  
Correction Term ◽  
Lithium Ion ◽  
Generalized Gradient ◽  
Main Group Metals ◽  
Generalized Gradient Approximation ◽  
Metal Insertion

<p></p><p>The generalized gradient approximation (GGA) often fails to correctly describe the electronic structure and thermochemistry of transition metal oxides and is commonly improved using an inexpensive correction term with a scaling parameter <i>U</i>. We tune <i>U</i> to reproduce experimental vanadium oxide redox energetics with a localized basis and a GGA functional. We find the value for <i>U</i> to be significantly lower than what is generally reported with plane-wave bases, with the uncorrected GGA results being in reasonable agreement with experiments. We use this computational setup to calculate interstitial and substitutional <a>insertion energies of main group metals in vanadium pentoxide</a> and find <a>interstitial doping to be thermodynamically favored</a>.</p><p></p>

Dissociation of dinitrogen on iron clusters: A detailed study of the Fe16 + N2 case.

2020 ◽  
Author(s):  
Bole Chen ◽  
Gennady L. Gutsev ◽  
Weiguo Sun ◽  
Xiao-Yu Kuang ◽  
Cheng Lu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Basis Set ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Iron Clusters ◽  
Generalized Gradient Approximation

The coalescence of two Fe8N as well as the structure of the Fe16N2 cluster were studied using density functional theory with the generalized gradient approximation and a basis set of...

Effect of Chromium and Vanadium on Nanolayered Ternary Carbides: AB Initio Study

2009 ◽  
Vol 609 ◽  
pp. 239-242
Author(s):  
A.E. Merad ◽  
M.B. Kanoun
Keyword(s):  
Electronic Structure ◽  
Total Energy ◽  
Ab Initio ◽  
Structural Parameters ◽  
Ab Initio Study ◽  
Generalized Gradient ◽  
Generalized Gradient Approximation ◽  
Full Relaxation ◽  
Relaxation Procedure ◽  
Ternary Carbides

The Cr2AlC and V2AlC nanolayered ternary carbides are studied by performing APW-lo ab initio total energy calculations within the recent Wu-Cohen generalized gradient approximation GGA. Using full relaxation procedure of the volume and the atomic positions we obtained the structural parameters and electronic structure of the optimization hexagonal. Results were compared with the experimental ones. Interesting features are deduced. In fact, we have shown why these materials are conductors.

scholarly journals Full-Potential Screened KKR Calculations for Magnetism of Co2MnSi, Ni2MnAl and Ru2MnSi, Based on the Generalized Gradient Approximation

2008 ◽  
Vol 49 (8) ◽  
pp. 1760-1767 ◽  
Author(s):  
M. Asato ◽  
M. Ohkubo ◽  
T. Hoshino ◽  
F. Nakamura ◽  
N. Fujima ◽  
...  
Keyword(s):  
Full Potential ◽  
Generalized Gradient ◽  
Generalized Gradient Approximation
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