Pattern Selection of Surface-based Nanostructures

2000 ◽  
Vol 648 ◽  
Author(s):  
E. G. Wang ◽  
B. G. Liu ◽  
J. Wu ◽  
W. G. Zhu ◽  
Z. Zhang
Keyword(s):  
First Principles ◽  
Film Growth ◽  
Kinetic Monte Carlo ◽  
Shielding Effect ◽  
Deposition Flux ◽  
Shape Transition ◽  
First Principles Calculations ◽  
Rich Variety ◽  
Kinetic Monte Carlo Simulations ◽  
Selection Of

AbstractA rich variety of two-dimensional patterns can be formed in the early stages of film growth. In this paper, we will show that, when a surfactant layer is used to mediate the growth, a counter-intuitive fractal-to-compact island shape transition can be induced by increasing deposition flux or decreasing growth temperature. Specifically, we introduce a reaction limited aggregation (RLA) theory, where the physical process controlling the island shape transition is the shielding effect of adatoms stuck to stable islands on incoming adatoms. Also discussed is the origin of a transition of compact islands from triangular to hexagonal then to inverted triangular in Pt (111) homoepitaxy with the presence of CO adsorbates. We will provide a coherent and unified picture for the interpretation of these intriguing observations based on kinetic Monte Carlo simulations, with energy barriers from first-principles calculations.

Multiscale modeling of charge transfer in polymers with flexible backbones

2019 ◽  
Vol 21 (4) ◽  
pp. 1812-1819 ◽  
Author(s):  
Masahiro Sato ◽  
Akiko Kumada ◽  
Kunihiko Hidaka
Keyword(s):  
First Principles ◽  
Kinetic Monte Carlo ◽  
First Principles Calculations ◽  
Multi Scale ◽  
Carrier Transfer ◽  
Scale Modeling ◽  
Kinetic Monte Carlo Simulations ◽  
Multi Scale Modeling ◽  
Dynamics Simulations ◽  
Transfer Properties

In order to evaluate carrier transfer properties in polymers with flexible backbones, we have proposed a simplified multi-scale modeling approach combining molecular dynamics simulations, first-principles calculations and kinetic Monte Carlo simulations.

Combined DFT and kinetic Monte Carlo study of a bridging-spillover mechanism on fluorine-decorating graphene

2020 ◽  
Author(s):  
Jing-hua Guo ◽  
Jin-Xiang Liu ◽  
Hongbo Wang ◽  
Haiying Liu ◽  
Gang Chen
Keyword(s):  
Monte Carlo ◽  
First Principles ◽  
Kinetic Monte Carlo ◽  
Monte Carlo Study ◽  
First Principles Calculations ◽  
Graphene Surface

In this work, combining the first-principles calculations with kinetic Monte Carlo (KMC) simulations, we constructed an irregular carbon bridge on the graphene surface and explored the process of H migration...

scholarly journals Strain Dependence of Energetics and Kinetics of Vacancy in Tungsten

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3375
Author(s):  
Zhong-Zhu Li ◽  
Yu-Hao Li ◽  
Qing-Yuan Ren ◽  
Fang-Fei Ma ◽  
Fang-Ya Yue ◽  
...  
Keyword(s):  
Binding Energy ◽  
First Principles ◽  
Tensile Strain ◽  
Kinetic Monte Carlo ◽  
Compressive Strain ◽  
Biaxial Strain ◽  
Poisson Effect ◽  
Vacancy Clusters ◽  
Object Kinetic Monte Carlo ◽  
Kinetic Monte Carlo Simulations

We investigate the influence of hydrostatic/biaxial strain on the formation, migration, and clustering of vacancy in tungsten (W) using a first-principles method, and show that the vacancy behaviors are strongly dependent on the strain. Both a monovacancy formation energy and a divacancy binding energy decrease with the increasing of compressive hydrostatic/biaxial strain, but increase with the increasing of tensile strain. Specifically, the binding energy of divacancy changes from negative to positive when the hydrostatic (biaxial) tensile strain is larger than 1.5% (2%). These results indicate that the compressive strain will facilitate the formation of monovacancy in W, while the tensile strain will enhance the attraction between vacancies. This can be attributed to the redistribution of electronic states of W atoms surrounding vacancy. Furthermore, although the migration energy of the monovacancy also exhibits a monotonic linear dependence on the hydrostatic strain, it shows a parabola with an opening down under the biaxial strain. Namely, the vacancy mobility will always be promoted by biaxial strain in W, almost independent of the sign of strain. Such unexpected anisotropic strain-enhanced vacancy mobility originates from the Poisson effect. On the basis of the first-principles results, the nucleation of vacancy clusters in strained W is further determined with the object kinetic Monte Carlo simulations. It is found that the formation time of tri-vacancy decrease significantly with the increasing of tensile strain, while the vacancy clusters are not observed in compressively strained W, indicating that the tensile strain can enhance the formation of voids. Our results provide a good reference for understanding the vacancy behaviors in W.

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