Molecular Dynamics Investigation of Interaction of Hydrogen Impurity with Twist Boundaries in Ni and Pd

2017 ◽  
Vol 60 (2) ◽  
pp. 201-205
Author(s):  
G. M. Poletaev ◽  
E. S. Medvedeva ◽  
I. V. Zorya ◽  
D. V. Novoselova ◽  
M. D. Starostenkov
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Impurity ◽  
Twist Boundaries

Interaction of Hydrogen Atom with Edge Dislocation in Pd and Ni

2018 ◽  
Vol 30 ◽  
pp. 46-51
Author(s):  
Irina V. Zorya ◽  
Gennady M. Poletaev ◽  
Mikhail D. Starostenkov
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Atom ◽  
Sorption Capacity ◽  
Edge Dislocation ◽  
Dislocation Core ◽  
Hydrogen Impurity ◽  
Hydrogen Atoms ◽  
Energy Characteristics ◽  
Method Of Molecular Dynamics ◽  
Diffusion Of Hydrogen

The energy characteristics of interaction of hydrogen impurity with ½<110> edge dislocation in Pd and Ni were calculated by the method of molecular dynamics. It is shown that the dislocation is effective trap for hydrogen. At the same time the dislocation jogs increases its sorption capacity with respect to hydrogen, but reduces the diffusion mobility of hydrogen along the dislocation. The diffusion of hydrogen atoms in the dislocation region occurs mainly along the dislocation core. The energy of hydrogen migration along the dislocation, as our calculations have shown, is almost two times lower than in a defect-free crystal.

Molecular Dynamics Investigation of the ∑5 Energy Cusp in [001] Twist Boundaries in Cu3Au at T=0 K

1996 ◽  
Vol 207-209 ◽  
pp. 833-836 ◽  
Author(s):  
I.P. Antoniades ◽  
A.J. Patrinos ◽  
G.L. Bleris
Keyword(s):  
Molecular Dynamics ◽  
Twist Boundaries

Theoretical Investigation of Twist Boundaries in Germanium

1986 ◽  
Vol 77 ◽  
Author(s):  
M. C. Payne ◽  
P. D. Bristowe ◽  
J. D. Joannopoulos
Keyword(s):  
Molecular Dynamics ◽  
Simulated Annealing ◽  
Grain Boundary ◽  
Low Energy ◽  
Energy Structure ◽  
Microscopic Structure ◽  
Twist Boundary ◽  
Small Contraction ◽  
Annealing Method ◽  
Twist Boundaries

ABSTRACTResults of the first completely ab-initio investigation of the microscopic structure of a grain boundary in a semiconductor are presented. Using the molecular dynamics simulated annealing method for performing total energy calculations within the LDA and pseudopotential approximations, the σ=5(001) twist boundary in germanium is studied. A low energy structure is identified which exhibits a rigid body translation and a small contraction at the boundary.

First-Principles Calculations and Molecular Dynamics Simulations on Effect of Hydrogen Impurity in Lead Titanate Films

2016 ◽  
Author(s):  
Lin Zhu ◽  
Jeong Ho You ◽  
Jinghong Chen
Keyword(s):  
Molecular Dynamics ◽  
First Principles ◽  
Hysteresis Loops ◽  
Md Simulations ◽  
Energy Difference ◽  
Effective Hamiltonian ◽  
First Principles Calculations ◽  
Hydrogen Impurity ◽  
Penalty Term ◽  
Energy Penalty

Properties of ferroelectric films are highly influenced by inevitable defects, such as hydrogen impurity. This study is focused on theoretical and numerical studies to probe effects of hydrogen contamination on ferroelectric stability in PbTiO3 (PTO) films using the first-principles effective Hamiltonian. First-principles calculations are performed to determine the possible position, formation energy, and mobility of hydrogen impurity atom, and the calculated results are used as inputs to molecular dynamics (MD) simulations in a large system. The hydrogen atom is able to move along the polarization with small energy barriers. The energy difference between a hydrogen contaminated PTO and a pure PTO is considered as an energy penalty term induced by hydrogen contamination and has been added to the effective Hamiltonian. Then, the MD effective Hamiltonian with the energy penalty is employed in MD simulations to investigate the effects of hydrogen contamination on the ferroelectric responses of PTO films with various thicknesses and temperatures. The hysteresis loops are presented and analyzed for PTO films with various concentrations of hydrogen impurities and thicknesses. Hydrogen contamination reduces the remnant polarization, especially for thin films. As the concentration of hydrogen impurities increases, the critical thickness increases. By analyzing the vertical cross section snapshots, it has been found that the hydrogen impurity atoms near interfaces affect the polarization throughout the entire PTO films.

MOLECULAR DYNAMICS STUDY OF THE STRUCTURE AND PROPERTIES OF TWIST BOUNDARIES

1988 ◽  
Vol 49 (C5) ◽  
pp. C5-139-C5-150 ◽  
Author(s):  
C. COUNTERMAN ◽  
L.-Q. CHEN ◽  
G. KALONJI
Keyword(s):  
Molecular Dynamics ◽  
Structure And Properties ◽  
Twist Boundaries

Role of point defects in self-diffusion along low-angle twist boundaries in fcc metals: A molecular dynamics study

2018 ◽  
Vol 03 (01n02) ◽  
pp. 1850001 ◽  
Author(s):  
G. M. Poletaev ◽  
I. V. Zorya ◽  
M. D. Starostenkov
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Point Defects ◽  
Binding Energies ◽  
Fcc Metals ◽  
Self Diffusion ◽  
Thermodynamic Equilibrium Condition ◽  
Dynamics Method ◽  
Twist Boundaries

The interaction of point defects with low-angle (100), (110) and (111) twist boundaries in fcc metals Ni, Cu, Al and role of the point defects in self-diffusion along considered boundaries were studied by the molecular dynamics method. The binding energies of point defects with low-angle twist boundaries were calculated. It was found that the point defects are mainly fixed in the nodes of grain-boundary screw dislocations network. It was shown that the introduced vacancies play an important role in diffusion along twist grain boundaries. The contribution of introduced interstitial atoms to grain-boundary diffusion under thermodynamic equilibrium condition is less by several orders of magnitude in comparison with the contribution of vacancies.

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