SIMULATION OF LAYER BY LAYER GROWTH OF FRACTAL METAL Pt-Rh FILMS

В данной работе методом молекулярной динамики с использованием потенциала сильной связи проведено моделирование процесса молекулярно-лучевой эпитаксии с целью определения закономерностей при формировании фрактальных металлических пленок платины на поверхности родия. Установлена возможность формирования фрактальных структур как в островковых пленках платины на поверхности родия, так и в сплошной пленке. Установлены параметры компьютерного эксперимента, определяющие переход от отдельных островковых пленок к сплошной пленке в указанной системе. С использованием различных программных продуктов Gwyddion и Image Analysis, а также собственной разработки FractalSurface проанализирован диапазон изменения фрактальной размерности при различных условиях молекулярно-динамического эксперимента методом подсчета кубов. Полученные значения фрактальной размерности в целом находятся в приемлемом согласии между собой, однако существует ряд исключений, которые обсуждаются более подробно. Сравнительный анализ получаемых результатов позволяет формулировать рекомендации для методики создания, корректировки и прецизионного контроля при «выращивании» структур с заданной морфологией поверхности. In this work, the molecular dynamics method and the tight-binding potential are used to simulate the process of molecular beam epitaxy in order to determine the regularities in the formation of fractal platinum metal films on the rhodium surface. The possibility of formation of fractal structures both in island platinum films on the rhodium surface and in a continuous film has been established. The parameters of the computer experiment, which determine the transition from individual island films to a continuous film in the indicated system, have been established. Using various software products Gwyddion and Image Analysis, as well as our own software FractalSurface, the range of changes in the fractal dimension has been analyzed under various conditions of a molecular dynamics experiment by the method of cube counting. The obtained values of the fractal dimension are generally in acceptable agreement with each other; however, there is a number of exceptions, which are discussed in more detail. A comparative analysis of the results obtained allows one to formulate recommendations for the methodology for creating, adjusting and precision control when «growing» structures with a given surface morphology.

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SIMULATION OF THE FRACTAL METAL FILMS FORMATION

Physical and Chemical Aspects of the Study of Clusters Nanostructures and Nanomaterials ◽

10.26456/pcascnn/2020.12.424 ◽

2020 ◽

pp. 424-437

Author(s):

Дмитрий Викторович Иванов ◽

Сергей Александрович Васильев ◽

Николай Юрьевич Сдобняков ◽

Елена Владимировна Романовская ◽

Виталий Александрович Анофриев ◽

...

Keyword(s):

Molecular Dynamics ◽

Molecular Beam ◽

Gold Film ◽

Tight Binding ◽

Copper Surface ◽

Metal Films ◽

Binding Potential ◽

Fractal Structures ◽

Software Product ◽

Dynamics Method

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An Investigation of PT/PT (111) Homoepitaxy with Molecular Dynamics Simulation and Static-Energy Calculation.

MRS Proceedings ◽

10.1557/proc-317-335 ◽

1993 ◽

Vol 317 ◽

Author(s):

Ruoping wang ◽

Bryan S. Kalp ◽

Kristen A. Fichthorn

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulation ◽

Film Growth ◽

Effective Medium Theory ◽

Layer Growth ◽

Dynamics Simulation ◽

Energy Calculation ◽

Layer By Layer ◽

Static Energy ◽

Step Edges

ABSTRACTWe present the results of a study of Pt/Pt (111) epitaxial thin-film growth with Molecular-dynamics simulation and static-energy calculation. Interatomic forces are modeled with Corrected-Effective-Medium theory. Atomic details of deposition, such as dissipation of the kinetic energy of an impinging gas atom, adatom motion on and approaching descending step edges, effects of the geometry of a step edge on the interlayer transport of adatoms, etc., have been intensively investigated. We have observed a novel mechanism for adatom incorporation into descending-step edges which involves a concerted motion of the adatom and edge atoms. Our study supports the “island size and shape” model which has been proposed to explain the reentrant layer-by-layer growth mode seen experimentally in Pt/Pt (111) homoepitaxy.

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Preparation, Structure, And Electronic Properties Of Amorphous Gaas By Tight-Binding Molecular Dynamics

MRS Proceedings ◽

10.1557/proc-321-135 ◽

1993 ◽

Vol 321 ◽

Author(s):

C. Molteni ◽

L. Colombo ◽

L. Miglio

Keyword(s):

Molecular Dynamics ◽

First Principles ◽

Large Scale ◽

Tight Binding ◽

Computer Experiment ◽

Dynamics Simulation ◽

First Principles Calculations ◽

Amorphous Network ◽

Large Scale Simulations

ABSTRACTWe investigate the short-range structural properties of a-GaAs as obtained in a computer experiment based on a tight-binding molecular dynamics simulation. The amorphous configuration is obtained by quenching a liquid sample well equilibrated at T=1600 K. A detailed characterization of the topology and defect distribution of the amorphous network is presented and discussed. The electronic structure of our sample is calculated as well. Finally, we discuss the reliability and transferability of the present computational scheme for large-scale simulations of compound semiconductor materials by comparing our results to first-principles calculations.

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Kinetic pathways leading to layer-by-layer growth from hyperthermal atoms: A multibillion time step molecular dynamics study

Physical Review B ◽

10.1103/physrevb.76.115418 ◽

2007 ◽

Vol 76 (11) ◽

Cited By ~ 15

Author(s):

D. Adamović ◽

V. Chirita ◽

E. P. Münger ◽

L. Hultman ◽

J. E. Greene

Keyword(s):

Molecular Dynamics ◽

Layer Growth ◽

Layer By Layer ◽

Time Step

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Molecular Dynamics Studies of Semiconductor Thin Films and Interfaces

MRS Proceedings ◽

10.1557/proc-94-15 ◽

1987 ◽

Vol 94 ◽

Cited By ~ 27

Author(s):

Marcia H. Grabow ◽

George H. Gilmer

Keyword(s):

Molecular Dynamics ◽

Energy State ◽

Layer Growth ◽

Metastable Equilibrium ◽

Free Energy Barrier ◽

Misfit Dislocations ◽

Layer By Layer ◽

3 Dimensional ◽

Smooth Film ◽

The Stability

ABSTRACTThe structure and stability of thin epitaxial films have been investigated using molecular dynamics computer simulations. One issue of interest is the stability of a smooth film relative to 3-dimensional clusters. The simulation results show that the uniform film is never the lowest energy state for a system with finite misfit. However, the uniform film, produced in a layer-by-layer growth mode, can persist in a metastable state at substantial misfits, e.g. 10% at 1/2 the melting point. This is a result of the large nucleation barrier to the formation of clusters.The second issue is the quality of the interface between the film and the substrate. At equilibrium, the critical thickness for the introduction of misfit dislocations is larger for films on the diamond cubic (100) substrate than on the (111), and differs from predictions based on continuum mechanics. We find that coherent films remain in metastable equilibrium far beyond the critical misfit calculated for full equilibrium, because a large free energy barrier inhibits the introduction of misfit dislocations.

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Effect of cooling rate on structural transformations in Ti-Al-V nanoalloy: molecular dynamics study

Journal of Physics Conference Series ◽

10.1088/1742-6596/2052/1/012038 ◽

2021 ◽

Vol 2052 (1) ◽

pp. 012038

Author(s):

N Yu Sdobnyakov ◽

V M Samsonov ◽

V S Myasnichenko ◽

P M Ershov ◽

A N Bazulev ◽

...

Keyword(s):

Molecular Dynamics ◽

Size Effect ◽

Cooling Rate ◽

Tight Binding ◽

Structural Transformations ◽

Rate Effect ◽

Binding Potential ◽

Cooling Rates ◽

Thermally Induced ◽

Local Structures

Abstract Using the isothermal molecular dynamics and the tight-binding potential, crystallization of Ti6Al4V nanodroplets was simulated. The objects of the research consisted of 2869 atoms, including 172 Al atoms and 115 V ones. The OVITO program was employed to recognize local structures and nanophases arisen in the course of cooling nanoalloy with the cooling rates of 0.1 and 0.4 K/ps. We have found that the cooling rate effect on the structure of the Ti6Al4V nanoalloy and the thermally induced structural transformations is much more pronounced than the size effect.

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Large-Scale Molecular Dynamics Simulations of Interstitial Defect Diffusion in Silicon

MRS Proceedings ◽

10.1557/proc-731-w9.10 ◽

2002 ◽

Vol 731 ◽

Cited By ~ 1

Author(s):

David A. Richie ◽

Jeongnim Kim ◽

Richard Hennig ◽

Kaden Hazzard ◽

Steve Barr ◽

...

Keyword(s):

Molecular Dynamics ◽

Large Scale ◽

Materials Science ◽

Tight Binding ◽

Md Simulations ◽

Binding Potential ◽

Interstitial Defect ◽

Long Time ◽

Computational Materials ◽

Dynamics Simulations

AbstractThe simulation of defect dynamics and evolution is a technologicaly relevant challenge for computational materials science. The diffusion of small defects in silicon unfolds as a sequence of structural transitions. The relative infrequency of transition events requires simulation over extremely long time scales. We simulate the diffusion of small interstitial clusters (I1, I2, I3) for a range of temperatures using large-scale molecular dynamics (MD) simulations with a realistic tight-binding potential. A total of 0.25 μ sec of simulation time is accumulated for the study. A novel real-time multiresolution analysis (RTMRA) technique extracts stable structures directly from the dynamics without structural relaxation. The discovered structures are relaxed to confirm their stability.

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Mechanical Behaviors of Nanoimprinted Cu-Ni Alloys Using Molecular Dynamics Simulation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.89-91.97 ◽

2010 ◽

Vol 89-91 ◽

pp. 97-101 ◽

Cited By ~ 1

Author(s):

Te Hua Fang ◽

Win Jin Chang ◽

Haw Long Lee ◽

Sie Jhan Wu

Keyword(s):

Molecular Dynamics ◽

Tight Binding ◽

Annealing Treatment ◽

Annealing Process ◽

Dynamics Simulation ◽

Binding Potential ◽

Mechanical Behaviors ◽

Ni Alloys ◽

Before And After ◽

Constant Heating

Molecular dynamics (MD) simulation with a tight-binding potential is used to studied the mechanical behaviors of nanoimprinted Cu-Ni alloys before and after annealing. The annealing process consists of three different stages. Initially, there is a gradual heating from the original temperature of 300 K to the specified annealing temperature of 823 K and then it is followed by a period of constant heating at that temperature, after which the specimen temperature is allowed to cool gradually to the original temperature. The results showed that when the punch is advancing, the punching force obtained from the simulation with a tight-binding potential is lower than with the Morse potential. The internal energy of Cu-Ni alloys decreased with increasing the temperature and the component of Cu during the annealing process. In addition, comparing the residual stress in the Cu-Ni alloys with and without annealing treatment, the stress is significantly released after annealing.

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SIZE DEPENDENCES OF LINEAR EXPANSION AND VOLUME ELASTICITY OF MONO- AND BIMETALLIC NANOCLUSTERS

Physical and Chemical Aspects of the Study of Clusters Nanostructures and Nanomaterials ◽

10.26456/pcascnn/2020.12.260 ◽

2020 ◽

pp. 260-273

Author(s):

Владимир Сергеевич Мясниченко ◽

Николай Юрьевич Сдобняков ◽

Анатолий Николаевич Базулев ◽

Павел Михайлович Ершов ◽

Екатерина Михайловна Давыденкова

Keyword(s):

Molecular Dynamics ◽

Analytical Model ◽

Expansion Coefficient ◽

Linear Expansion ◽

Tight Binding ◽

Relative Increase ◽

Binding Potential ◽

Linear Expansion Coefficient ◽

Bimetallic Nanoclusters ◽

Coefficient Of Linear Expansion

Проведена серия молекулярно-динамических экспериментов по охлаждению разупорядоченных металлических наночастиц Au, Cu, Al,Ti и биметаллических наносплавов Au - Cu и Ti - Al с использованием потенциала сильной связи. Получены размерные зависимости коэффициента линейного расширения и модуля упругости для моно- и биметаллических частиц. В первом приближении размерная зависимость коэффициента линейного расширения обратно пропорциональна соответствующей зависимости для температуры плавления наночастицы, что коррелирует с аналитической моделью. Молекулярно-динамические результаты предсказывают более умеренный относительный рост коэффициента линейного расширения, по сравнению с аналитической моделью. Установлено, что модуль упругости увеличивается с уменьшением размера наночастиц. A series of molecular dynamics experiments on cooling disordered Au,Cu, Al,Ti metal nanoparticles and Au - Cu, Ti - Al bimetallic nanoalloys using the tight-binding potential have been performed. The size dependences of the temperature coefficient of linear expansion and the elasticity modulus for mono- and bimetallic particles are obtained. In the first approximation, the size dependence of the linear expansion coefficient is inversely proportional to the corresponding dependence for the melting temperature of a nanoparticle, which correlates with an analytical model. Molecular dynamics results predict a more moderate relative increase in the linear expansion coefficient compared to the analytical model. It was found that the modulus of elasticity increases with decreasing the nanoparticle size.

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A Molecular Dynamics Study of the Terminal Zr(Ni) Solid Solutions

MRS Proceedings ◽

10.1557/proc-400-131 ◽

1995 ◽

Vol 400 ◽

Author(s):

F. Cleri ◽

G. Mazzone ◽

V. Rosato

Keyword(s):

Molecular Dynamics ◽

Phase Diagram ◽

Solid Solutions ◽

Tight Binding ◽

Solid State Reactions ◽

Binding Potential ◽

Terminal Portion ◽

Many Body ◽

Empirical Phase Diagram ◽

Dynamics Simulations

AbstractThe Zr terminal portion of the Zr-Ni phase diagram has been evaluated by means of a many-body tight-binding potential. The internal energy curves of the Zr(Ni) solid solutions at T=300 K have been calculated by Molecular Dynamics simulations. These curves exhibit positive values, contrary to former empirical phase diagram calculations. Implications of these results relevant to the problem of amorphization in metallic systems by solid-state reactions are discussed.

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