Vacancy-Mediated Diffusion and Diffusion-Controlled Processes in Ordered Binary Intermetallics by Kinetic Monte Carlo Simulations

2021 ◽  
Vol 29 ◽  
pp. 95-115
Author(s):  
Rafal Kozubski ◽  
Graeme E. Murch ◽  
Irina V. Belova
Keyword(s):  
Monte Carlo ◽  
Kinetic Monte Carlo ◽  
Simulation Studies ◽  
Self Diffusion ◽  
Monte Carlo Techniques ◽  
Diffusion Controlled ◽  
Kinetic Monte Carlo Simulations ◽  
Kinetic Effects ◽  
Kinetics Of ◽  
And Diffusion

We review the results of our Monte Carlo simulation studies carried out within the past two decades in the area of atomic-migration-controlled phenomena in intermetallic compounds. The review aims at showing the high potential of Monte Carlo methods in modelling both the equilibrium states of the systems and the kinetics of the running processes. We focus on three particular problems: (i) the atomistic origin of the complexity of the ‘order-order’ relaxations in γ’-Ni3Al; (ii) surface-induced ordering phenomena in γ-FePt and (iii) ‘order—order’ kinetics and self-diffusion in the ‘triple-defect’ β-NiAl. The latter investigation demonstrated how diverse Monte Carlo techniques may be used to model the phenomena where equilibrium thermodynamics interplays and competes with kinetic effects.

Kinetics of palladium particles on LiNbO3: an origin of the polarization-dependent catalysis

2012 ◽  
Vol 1397 ◽  
Author(s):  
Seungchul Kim ◽  
Michael Rutenberg Schoenberg ◽  
Andrew M. Rappe
Keyword(s):  
Monte Carlo ◽  
Catalytic Activity ◽  
Kinetic Monte Carlo ◽  
Polarization Direction ◽  
Atomic Structures ◽  
Negative Surface ◽  
Kinetic Monte Carlo Simulations ◽  
Pd Clusters ◽  
Palladium Particles ◽  
Kinetics Of

ABSTRACTUsing ab-initio calculations and kinetic Monte Carlo simulations, we demonstrate that the deposition geometries of palladium are strongly dependent on the polarization direction of the LiNbO3 substrate. Different stoichiometries and atomic structures of the positively and the negatively polarized substrates cause substantially different bonding configurations of palladium and energy barriers for the movement of Pd clusters. Our simulations predict that palladium atoms form bulky clusters on the positive surface, while they are deposited in a dispersed or planar manner on the negative surface at moderate temperature. We suggest that Inoue and coworkers’ observation [J. Phys. Chem.88, 1148 (1984)] that the catalytic activity of palladium depends on polarization direction of LiNbO3 substrate is, at least in part, due to differences in the geometric structures of palladium and the LiNbO3 surface.

Ab initio study of Ge Adsorption on H-terminated Si(001) Surfaces

2000 ◽  
Vol 648 ◽  
Author(s):  
Takahisa Ohno ◽  
Jun Nara ◽  
Takahide Ezaki
Keyword(s):  
Monte Carlo ◽  
Total Energy ◽  
First Principles ◽  
Diffusion Processes ◽  
Kinetic Monte Carlo ◽  
Ab Initio Study ◽  
Kinetic Monte Carlo Simulations ◽  
Site Exchange ◽  
Adsorption Geometry ◽  
And Diffusion

AbstractThe Ge adsorption and diffusion processes on the monohydride terminated Si(001) surface are investigated by using first-principles total-energy calculations and kinetic Monte Carlo simulations. We find that the adsorbed Ge atoms tend to exchange sites with substrate Si dimer atoms. The site exchange plays an important role, which provides the most stable geometry and the easiest diffusion pathway. The Ge adatom migrates in the subsurface region instead of on the surface. The temporal variation in the adsorption geometry during diffusion is found. The Si atoms can become the surface diffusion species instead of the Ge atoms, as a result of the site exchange.

scholarly journals Kinetic lattice Monte-Carlo simulations on the ordering kinetics of free and supported FePt L10-nanoparticles

2011 ◽  
Vol 2 ◽  
pp. 40-46 ◽  
Author(s):  
Michael Müller ◽  
Karsten Albe
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Kinetic Monte Carlo ◽  
Bulk Diffusion ◽  
Particle Volume ◽  
Ordering Kinetics ◽  
Kinetic Monte Carlo Simulations ◽  
Thermodynamic Driving Force ◽  
Interface Segregation ◽  
Kinetics Of

The ordering kinetics in free and supported L10 nanoparticles was studied by means of lattice-based kinetic Monte-Carlo simulations. Starting from a fully disordered particle of Wulff shape, the simulations show that the nucleation of ordered domains is starting quickly on various (100) facets but is retarded in the particle volume due to the lack of vacancies compared with a thin film geometry. If a substrate is present, we do not find significant differences in the ordering behavior. This holds true, even if we impose a massively increased thermodynamic driving force for interface segregation, because the nucleation of ordered domains on free facets is significantly faster than the bulk diffusion of the segregating species to the interface. In cases where wetting of the substrate or surface facetting occurs, we find that diffusional atomic motion on the surface goes along with an enhanced long-range order.

SIMULATION STUDIES OF THE IMPURE ATOMS DIFFUSION ON Cu(001) SURFACE

2004 ◽  
Vol 18 (17n19) ◽  
pp. 2766-2770
Author(s):  
GUOCE ZHUANG
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Critical Point ◽  
Kinetic Monte Carlo ◽  
Diffusion Mechanism ◽  
Indium Atom ◽  
Simulation Studies ◽  
Kinetic Monte Carlo Simulations ◽  
Simulation Results ◽  
Close Packed Layer

Based on the vacancy-assisted diffusion mechanism, the impure atomic moving processes on the close-packed layer of a Cu (001) surface are studied by kinetic Monte Carlo simulations. Our simulation results show that the diffusivity of the Indium atom agrees quite well with the exact lattice solution. In addition, it is found that in the case of muti-impure atoms, there exist a critical point near the value of ∊=0, and the diffusivity of In atom depends on the number of impure atoms only when ∊ is positive.

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