NONEMPIRICAL SIMULATIONS OF Σ3< 111> TUNGSTEN GRAIN BOUNDARY WITH BORON ATOMS

We perform the atomistic simulations of the properties of the Σ3< 111> grain boundary in W and demonstrate the influence of boron additive on the resistance of the grain boundary with respect to different shifts. The interatomic potentials used in these simulations are obtained from ab initio total energy calculations. These calculations are carried out in the framework of density functional theory in the coherent potential approximation. The recursion procedure to extract A–B type interatomic potentials is suggested.

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Modeling of Boron Adsorption on the (110) Tungsten Surface

Surface Review and Letters ◽

10.1142/s0218625x03004846 ◽

2003 ◽

Vol 10 (02n03) ◽

pp. 213-219 ◽

Cited By ~ 1

Author(s):

Simon Dorfman ◽

Ronan R. Braga ◽

Kleber C. Mundim ◽

David Fuks

Keyword(s):

Density Functional Theory ◽

Total Energy ◽

Density Functional ◽

Atomistic Simulations ◽

Interatomic Potentials ◽

Potential Approximation ◽

Functional Theory ◽

Tungsten Surface ◽

Adhesion Process ◽

Boron Adsorption

We have performed the atomistic simulations of the adhesion process of a boron atom on the tungsten (110) surface on the basis of the generalized simulation annealing formalism. The interatomic potentials used in these simulations were obtained from ab initio total energy calculations on the basis of the recursion procedure. The nonempirical calculations have been carried out in the framework of density functional theory in the coherent potential approximation.

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Density-Functional Theory for Random Alloys: Total Energy within the Coherent-Potential Approximation

Physical Review Letters ◽

10.1103/physrevlett.56.2088 ◽

1986 ◽

Vol 56 (19) ◽

pp. 2088-2091 ◽

Cited By ~ 187

Author(s):

D. D. Johnson ◽

D. M. Nicholson ◽

F. J. Pinski ◽

B. L. Gyorffy ◽

G. M. Stocks

Keyword(s):

Density Functional Theory ◽

Total Energy ◽

Density Functional ◽

Coherent Potential Approximation ◽

Potential Approximation ◽

Functional Theory ◽

Random Alloys

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ATOMIC STRUCTURE STUDY OF THE Ag/MgO(100) SURFACE BY AN AB INITIO, TOTAL ENERGY MOLECULAR CLUSTER METHOD USING DENSITY FUNCTIONAL THEORY

Surface Review and Letters ◽

10.1142/s0218625x96002370 ◽

1996 ◽

Vol 03 (03) ◽

pp. 1365-1375 ◽

Cited By ~ 13

Author(s):

LAURENT SPIESS

Keyword(s):

Density Functional Theory ◽

Total Energy ◽

Ab Initio ◽

Density Functional ◽

Structure Study ◽

Cluster Method ◽

Molecular Cluster ◽

Functional Theory ◽

Molecular Systems ◽

Coverage Dependence

The clean and Ag-covered MgO(100) surface is investigated by an all-electron, total energy, ab initio DMol molecular method (Density functional theory for Molecular systems). A large cluster of 100 atoms (including 50 oxygen and 50 magnesium) is built to represent the surface. A point charge embedding is used to investigate the electronic properties. The small relaxation of the surface, referred to as rumpling, is exhibited and shown to have barely no effect on the adsorption of Ag on the surface. The oxygen site is found to be the most stable for Ag atom adsorption, in good agreement with previous ab initio theoretical studies. The adsorption of a five-Ag-atom layer on the MgO(100) surface provides new and interesting results concerning the surface coverage dependence. We have used the unique ability of cluster methods to study the structural effects of the 3% mismatch at the Ag/MgO(100) interface, and we show that Ag atoms are likely to grow on the surface without epitaxy at low coverages.

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DISSOCIATION OF PH3 AND AsH3 ON Ge(100)(2x1) SURFACE

Surface Review and Letters ◽

10.1142/s0218625x07009451 ◽

2007 ◽

Vol 14 (03) ◽

pp. 507-515 ◽

Cited By ~ 4

Author(s):

ŞENAY KATIRCIOĞLU

Keyword(s):

Density Functional Theory ◽

Total Energy ◽

Density Functional ◽

Functional Theory ◽

Energy Calculations ◽

Dissociation Path ◽

Stable Structures ◽

Relative Total Energy

The most stable structures for the dissociation of phosphine and arsine on Ge (100)(2x1) surface have been investigated by relative total energy calculations based on Density Functional Theory. It has been found that the thermodynamically preferred structures in the dissociation path of phosphine and arsine are the same; PH 2 and AsH 2 products prefer to be on a single Ge dimer bond, but PH and AsH prefer to be between the adjacent Ge dimers. According to the optimization calculations, the dissociation path started with the adsorption of PH 3( AsH 3) on the electron deficient side of the Ge dimer bond is ended with the formation of P – P ( As – As ) dimers parallel to the dimers of Ge .

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New Insight in Scandium-Mediated Growth Techniques: Sc-Related Defects in 4H-SiC and 6H-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.556-557.469 ◽

2007 ◽

Vol 556-557 ◽

pp. 469-472 ◽

Cited By ~ 1

Author(s):

Uwe Gerstmann ◽

Siegmund Greulich-Weber ◽

E. Rauls ◽

Johann Martin Spaeth ◽

Ekaterina N. Kalabukhova ◽

...

Keyword(s):

Density Functional Theory ◽

Total Energy ◽

Density Functional ◽

Epr Spectra ◽

Functional Theory ◽

Energy Calculations ◽

Large Anisotropy

Scandium can be used to influence the stoichiometry of SiC during growth of the hexagonal polytypes. Using PL-EPR and total energy calculations in the framework of density functional theory, scandium is predicted to be built in predominantly at the Si-sublattice in form of ScSi acceptors with acceptor levels at 0.55 eV (6H-SiC) and 0.48 eV (4H-SiC). In addition, new PL-EPR spectra are found with a large anisotropy in the g-tensor suggesting defect pairs as an origin.

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Modelling Hydrogen Embrittlement using Density Functional Theory: A theoretical approach to understanding environmentally assisted cracking in 7xxx series aluminium alloys

MATEC Web of Conferences ◽

10.1051/matecconf/202032604006 ◽

2020 ◽

Vol 326 ◽

pp. 04006

Author(s):

Benjamin T. Wilson ◽

Joseph D. Robson ◽

Christopher P. Race

Keyword(s):

Density Functional Theory ◽

Grain Boundary ◽

Grain Boundaries ◽

Cohesive Zone ◽

Density Functional ◽

Atomistic Simulations ◽

Functional Theory ◽

Minimal Impact ◽

Symmetric Tilt ◽

Environmentally Assisted Cracking

The effects of H segregation to a Σ11 symmetric tilt Al grain boundary are investigated using atomistic simulations, as part of a wider study on cracking in 7xxx series alloys. Density functional theory based simulations of uniaxial straining of grain boundaries containing 11 different concentrations of H were performed under the cohesive zone fracture mechanics framework. The theoretical strength of grain boundaries is shown to be supressed by H segregation, and the cause of this is attributed to the prevention of the formation of Al ligaments across grain boundaries. Segregated concentrations of relevant alloying elements (Zn, Mg, and Cu) show minimal impact on the H embrittlement process investigated, namely H enhanced decohesion (HEDE). Further modelling, of H transport and grain boundary precipitates, is required to confirm the validity of the HEDE mechanism in the case of 7xxx alloys.

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