Relation of Phase Stability Boundary to the Fill-Up Bonding States In Ni3V,Co3V and Fe3V

1990 ◽  
Vol 213 ◽  
Author(s):  
W. Lin ◽  
Jian-Hua Xu ◽  
A.J. Freeman
Keyword(s):  
Structural Stability ◽  
Electronic Structures ◽  
Local Density ◽  
Stability Boundary ◽  
The Self ◽  
Orbital Method ◽  
Density Approximation ◽  
Cohesive Properties ◽  
Self Consistent ◽  
Electronic Concentration

ABSTRACTThe electronic structures and cohesive properties of the intermetallics Ni3V, Co3V, and Fe3V in the L12 structure have been studied using the self-consistent total energy linear muffin-tin orbital method based on the local density approximation. The simple rigid-band concept appears to be adequate to explain the structural stability of these compounds. Further,the structural stability of the pseudobinary compounds (Ni,Co,Fe)3V has been investigated based on the rigid-band scheme. The correlation between the electronic concentration and the crystal structure is shown to be related to the fill-up of the bonding states.

Bandfilling and structural stability of trialuminides: YAl3, ZrAl3, and NbAl3

1991 ◽  
Vol 6 (6) ◽  
pp. 1188-1199 ◽  
Author(s):  
Jian-hua Xu ◽  
A.J. Freeman
Keyword(s):  
Transition Metal ◽  
Structural Stability ◽  
Electronic Structures ◽  
Local Density ◽  
Metal Carbides ◽  
Metal Compounds ◽  
Cohesive Properties ◽  
Valence Electrons ◽  
Stable Forms ◽  
Covalent Interactions

The cohesive properties and electronic structures versus the structural stability of transition-metal trialuminides YAl3, ZrAl3, and NbAl3 in their cubic L12, tetragonal DO22, and naturally stable forms (i.e., the DO19 structure for YAl3 and the DO23 structure for ZrAl3) have been investigated using a total energy local-density approach. The variation of structural stability with transition-metal constituent can be simply understood in terms of the bandfilling of the bonding states in the rigid band sense, with the valence electrons gradually filling the bonding states on going from YAl3, ZrAl3 to NbAl3. This leads to a phase transition from the cubic L12 structure (for YAl3) to the tetragonal DO22 structure (for NbAl3). It is argued that this criterion may also apply to explain the variation of the structural stability of other transition-metal compounds (such as transition-metal carbides, nitrides, silicides, etc.) that are dominated by covalent interactions between the transition-metal d and the metalloid p states.

Self-consistent-field calculations of atoms and ions using a modified local-density approximation

1994 ◽  
Vol 50 (1) ◽  
pp. 171-176 ◽  
Author(s):  
David A. Liberman ◽  
James R. Albritton ◽  
Brian G. Wilson ◽  
William E. Alley
Keyword(s):  
Local Density Approximation ◽  
Local Density ◽  
Density Approximation ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field

A comparative study on the LDA + U and hybrid functional methods on the description of the electronic structure of YTiO3 under high pressure

2009 ◽  
Vol 87 (10) ◽  
pp. 1374-1382 ◽  
Author(s):  
Z. Song ◽  
J. J. Yang ◽  
J. S. Tse
Keyword(s):  
Electronic Structures ◽  
Local Density ◽  
Band Gaps ◽  
Density Approximation ◽  
Hybrid Functional ◽  
Functional Methods ◽  
Mixing Parameters ◽  
Hubbard U ◽  
Hubbard Parameter ◽  
Pressure Analysis

The electronic structures of YTiO3 under pressure have been studied with LDA + U (local density approximation + Hubbard parameter) and hybrid functional methods. From matching the experimental band gaps, the Hubbard U and hybrid functional mixing parameters were determined. It is found that both parameters vary with the pressure. Analysis of the electronic structures indicates that the description of the chemical bonding is also dependent on the method of choice.

Tight-Binding Study of the {211} Σ=3 Grain Boundary in Cubic Silicon-Carbide

1994 ◽  
Vol 339 ◽  
Author(s):  
M. Kohyama ◽  
R. Yamamoto
Keyword(s):  
Grain Boundaries ◽  
Electronic Structures ◽  
Tight Binding ◽  
The Self ◽  
Localized States ◽  
General Definition ◽  
Self Consistent ◽  
Tight Binding Method ◽  
Definition Of ◽  
Cubic Silicon Carbide

ABSTRACTIn grain boundaries in compound semiconductors such as SiC, the interface stoichiometry and the wrong bonds between like atoms are of much importance. Firstly, a general definition of the interface stoichiometry in such grain boundaries has been discussed. Secondly, the atomic and electronic structures of the {211} Σ=3 boundary in SiC have been examined by using the self-consistent tight-binding method, based on the atomic models with bonding networks similar to those in the models of the same boundary in Si or Ge. The wrong bonds have significant effects through the large electrostatic repulsion and the generation of localized states as well as those in the {122} Σ=9 boundary in SiC. And the different bond lengths of the wrong bonds very much affect the local bond distortions at the interfaces, which determines the relative stability among the present models.

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.

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