Simulations of Low-Energy Ion/Surface Interaction Effects During Epitaxial Film Growth.

1991 ◽  
Vol 223 ◽  
Author(s):  
Makoto Kitabatake ◽  
J. E. Greene
Keyword(s):  
Film Growth ◽  
Low Energy ◽  
Many Body ◽  
Energy Redistribution ◽  
Mbe Growth ◽  
Lattice Atom ◽  
Site Exchange ◽  
Dynamics Simulations ◽  
Body Potential ◽  
Epitaxial Film Growth

ABSTRACTMolecular dynamics simulations were used to follow low-energy ion/surface interactions including kinetic energy redistribution in the lattice as a function of time, projectile and lattice atom trajectories, and the nature, number, and depth of residual defects. The simulations were carried out using the Tersoff many-body potential for Si. Irradiation events were initiated with 10 and 50 eV Si atoms incident normal to the Si(001)2×l surface at an array of points in the primitive surface unit cell. Ion-induced epitaxial growth was observed due to both Si projectiles and Si lattice atoms coming to rest at epitaxial positions through direct deposition as well as site exchange occurring via diffusional and collisional processes. 36 simulations of 10 eV (50 eV) Si bombardment resulted in an average stopping position of 0.5 Å (1.6 Å) below the surface, 10 (13) epitaxial events, 7 (24) exchange events between the projectile and a lattice atom, and the formation of 15 (63) interstitials and 0 (36) vacancies. The interstitials preferentially diffuse toward the surface and are annealed out over times corresponding to monolayer deposition at typical Si MBE growth temperatures.

Low Energy Si Bombardment Effects on Epitaxial Si Growth

1992 ◽  
Vol 268 ◽  
Author(s):  
Makoto Kitabatake ◽  
J. E. Greene
Keyword(s):  
Surface Interactions ◽  
Low Energy ◽  
Many Body ◽  
Exchange Reactions ◽  
Energy Redistribution ◽  
Mbe Growth ◽  
Lattice Atom ◽  
Dynamics Simulations ◽  
Body Potential ◽  
Surface Unit Cell

ABSTRACTMolecular dynamics simulations were used to follow low-energy ion/surface interactions in Si MBE including kinetic energy redistribution in the lattice as a function of time, projectile and lattice atom trajectories, and the nature, number, and depth of residual defects. The simulations were carried out using the Tersoff many-body potential for Si. Irradiation events were initiated with 10 and 50 eV Si atoms incident normal to the Si(001)2xl surface at an array of points in the primitive surface unit cell. Epitaxy, exchange reactions, and defect (vacancy and interstitial) formations were observed. Quasidynamic simulations suggested that the interstitials preferentially diffuse toward the surface and are annealed out over times corresponding to monolayer deposition at typical Si MBE growth temperatures.

Molecular Dynamics Simulations of Low-Energy Ion/Surface Interactions During Vapor Phase Crystal Growth: 10 eV Si Incident on Si(001)2×1

1989 ◽  
Vol 157 ◽  
Author(s):  
M. Kitabatake ◽  
P. Fons ◽  
J. E. Greene
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Unit Cell ◽  
Many Body ◽  
Energy Redistribution ◽  
Surface Unit ◽  
Phase Crystal ◽  
Dynamics Simulations ◽  
Body Potential ◽  
Surface Unit Cell

ABSTRACTMolecular dynamics simulations, utilizing the Tersoff many-body potential, were used to investigate the effects of 10 eV Si atom bombardment of a (001)2×1 terminated Si lattice. The irradiation events were initiated at an array of points in the primitive surface unit cell. Each event was followed to determine kinetic energy redistribution in the lattice as a function of time, projectile and lattice atom trajectories, and the nature, number, and depth of residual defects. Dimer breaking, epitaxial growth, position exchange, and the formation of residual hexagonal and split interstitials were observed. There were no residual vacancies. Impact points leading to each of the above results clustered in distinctly different regions of the surface unit cell. Bulk interstitials were annealed out over time scales corresponding to monolayer deposition during Si MBE.

Data-Driven Many-Body Models with Chemical Accuracy for CH4/H2O Mixtures

2020 ◽  
Author(s):  
Marc Riera ◽  
Alan Hirales ◽  
Raja Ghosh ◽  
Francesco Paesani
Keyword(s):  
Liquid Phase ◽  
Quantitative Description ◽  
Liquid Mixtures ◽  
Many Body ◽  
Energy Functions ◽  
Potential Energy Functions ◽  
Dynamics Simulations ◽  
Body Potential ◽  
Small Clusters ◽  
Many Body Interactions

<div> <div> <div> <p>Many-body potential energy functions (PEFs) based on the TTM-nrg and MB-nrg theoretical/computational frameworks are developed from coupled cluster reference data for neat methane and mixed methane/water systems. It is shown that that the MB-nrg PEFs achieve subchemical accuracy in the representation of individual many-body effects in small clusters and enables predictive simulations from the gas to the liquid phase. Analysis of structural properties calculated from molecular dynamics simulations of liquid methane and methane/water mixtures using both TTM-nrg and MB-nrg PEFs indicates that, while accounting for polarization effects is important for a correct description of many-body interactions in the liquid phase, an accurate representation of short-range interactions, as provided by the MB-nrg PEFs, is necessary for a quantitative description of the local solvation structure in liquid mixtures. </p> </div> </div> </div>

scholarly journals Large-scale molecular dynamics simulations of TiN/TiN(001) epitaxial film growth

2016 ◽  
Vol 34 (4) ◽  
pp. 041509 ◽  
Author(s):  
Daniel Edström ◽  
Davide G. Sangiovanni ◽  
Lars Hultman ◽  
Ivan Petrov ◽  
J. E. Greene ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Large Scale ◽  
Epitaxial Film ◽  
Film Growth ◽  
Dynamics Simulations ◽  
Epitaxial Film Growth

Molecular Dynamics Simulation of Sputtering with Mmany-Body Interactions

1988 ◽  
Vol 100 ◽  
Author(s):  
Davy Y. Lo ◽  
Tom A. Tombrello ◽  
Mark H. Shapiro ◽  
Don E. Harrison
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Single Crystal ◽  
Low Energy ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Many Body ◽  
Embedded Atom ◽  
Dynamics Simulations ◽  
Small Single Crystal

ABSTRACTMany-body forces obtained by the Embedded-Atom Method (EAM) [41 are incorporated into the description of low energy collisions and surface ejection processes in molecular dynamics simulations of sputtering from metal targets. Bombardments of small, single crystal Cu targets (400–500 atoms) in three different orientations ({100}, {110}, {111}) by 5 keV Ar+ ions have been simulated. The results are compared to simulations using purely pair-wise additive interactions. Significant differences in the spectra of ejected atoms are found.

GLOBAL MINIMA FOR PdN (N = 5–80) CLUSTERS DESCRIBED BY SUTTON–CHEN POTENTIAL

2007 ◽  
Vol 18 (08) ◽  
pp. 1351-1359 ◽  
Author(s):  
HAYDAR ARSLAN
Keyword(s):  
Monte Carlo ◽  
Energy Surface ◽  
Central Atom ◽  
Low Energy ◽  
Global Minima ◽  
Many Body ◽  
Pd Clusters ◽  
Body Potential ◽  
Basin Hopping ◽  
Theoretical Results

The structure and energetics of Pd N (N = 5–80) clusters have been studied extensively by a Monte Carlo method based on Sutton–Chen many-body potential. The basin-hopping algorithm is used to find the low-energy minima on the potential energy surface for each nuclearity. A variety of structure types (icosahedral, decahedral and fcc closed-packed) are observed for Pd clusters. Some of the icosahedral global minima do not have a central atom. The resulting structures have been compared with the previous theoretical results.

EFFECT OF CHIRALITY ON THE STABILITY OF CARBON NANOTUBES: MOLECULAR-DYNAMICS SIMULATIONS

2001 ◽  
Vol 12 (06) ◽  
pp. 865-870 ◽  
Author(s):  
ŞAKIR ERKOÇ ◽  
OSMAN BARIŞ MALCIOĞLU
Keyword(s):  
Heat Treatment ◽  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Potential Energy Function ◽  
Single Wall Carbon Nanotubes ◽  
Many Body ◽  
Chiral Structure ◽  
The Stability ◽  
Dynamics Simulations ◽  
Body Potential

The effect of chirality on the structural stability of single-wall carbon nanotubes have been investigated by performing molecular-dynamics computer simulations. Calculations have been realized by using an empirical many-body potential energy function for carbon. It has been found that carbon nanotube in chiral structure is more stable under heat treatment relative to zigzag and armchair models. The diameter of the tubes is slightly enlarged under heat treatment.

Molecular-Dynamics Simulations of Collisions of Buckminsterfullerene with Diamond Surfaces

1990 ◽  
Vol 206 ◽  
Author(s):  
R.C. Mowrey ◽  
D.W. Brenner ◽  
B.I. Dunlap ◽  
J.W. Mintmire ◽  
C.T. White
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Center Of Mass ◽  
Potential Energy Function ◽  
Diamond Surface ◽  
Many Body ◽  
Diamond Surfaces ◽  
Gas Phase Dissociation ◽  
Dynamics Simulations ◽  
Body Potential

ABSTRACTWe have performed molecular dynamics simulations using a recently developed empirical many-body potential energy function to study the collision of the C60 isomer buckmin-sterfullerene with a hydrogen-terminated diamond surface. The simulations indicate that the cluster can react with the surface and has a larger probability of gaining atoms from the surface than of losing atoms to the surface. We have investigated the dependence of the reaction probability on the initial center-of-mass translational velocity of the cluster. The structures and energy distributions of the product clusters have been determined. Both inelastically and reactively scattered clusters have large amounts of internal energy which suggests that gas-phase dissociation is likely.

Molecular Dynamics Simulations of Low-Energy Atom-Surface Interactions

1992 ◽  
Vol 268 ◽  
Author(s):  
J. A. Sprague ◽  
C. M. Gilmore
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Film Growth ◽  
Low Frequency ◽  
Exchange Interactions ◽  
Low Energy ◽  
Growth Surface ◽  
Surface Exchange ◽  
Oriented Film ◽  
Dynamics Simulations

ABSTRACTMolecular dynamics simulations of the deposition of atoms on crystalline surfaces have been conducted using the embedded atom method. The following atom-substrate combinations have been employed: 0.1 - 40 eV Ag deposited on (111) and (100) Ag substrates; 0.1 eV Ag deposited on (100) Cu; and 0.1 eV Cu deposited on (100) Ag. The purpose of the calculations for Ag atoms deposited on Ag substrates was to investigate the effects of adatom arrival energy and substrate orientation on the interactions of low-energy atoms with crystal surfaces. The goal of tile Ag oil Cu and Cu on Ag calculations was to observe the mechanisms producing thepreviously-reported asymmetry in epitaxy for these systems. The Ag on Ag deposition simulations demonstrated that the effects of increased atom arrival energies in promoting layerby- layer film growth and producing diffuse substrate-filn interfaces (mixing) were basically the same on the (100) and (111) surfaces. At 0. 1 eV, representative of thennal evaporation, the degree of island formation on the (100) substrate was essentially tile same as previously reported for a (111) Ag substrate. At a given atom arrival energy between 10 and 40 eV, both the redistribution into full monolayers and the mixing by surface exchange interactions were seen to occur more readily on the close-packed (111) growth surface than on the more open (100) surface. The mixing was a stronger function of crystallographic orientation. Cu was observed to grow on (100) Ag as a (100)-oriented film, with the initial film layers transfonned essentially to the bcc structure by a Bain distortion, in agreement with various experimental results. The distortion of the film layers resulted in large-amplitude soft-mode (low-frequency) lattice vibrations. Ag was observed to grow on (100) Cu as a (111)-oriented film, as experimentally observed, with the <110>-type orientations of film and substrate parallel, as predicted by previous calculations of interfacial energy.

scholarly journals Elevating Density Functional Theory to Chemical Accuracy for Water Simulations through a Density-Corrected Many-Body Formalism

2021 ◽  
Author(s):  
Saswata Dasgupta ◽  
Eleftherios Lambros ◽  
John Perdew ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Water Clusters ◽  
Potential Energy Function ◽  
Data Driven ◽  
Coupled Cluster ◽  
Many Body ◽  
Functional Theory ◽  
Dynamics Simulations ◽  
Body Potential

Density functional theory (DFT) has been extensively used to model the properties of water. Albeit maintaining a good balance between accuracy and efficiency, no density functional has so far achieved the degree of accuracy necessary to correctly predict the properties of water across the entire phase diagram. Here, we present density-corrected SCAN (DC-SCAN) calculations for water which, minimizing density-driven errors, elevate the accuracy of the SCAN functional to that of “gold standard” coupled-cluster theory. Building upon the accuracy of DC-SCAN within a many-body formalism, we introduce a data-driven many-body potential energy function, MB-SCAN(DC), that quantitatively reproduces coupled cluster reference values for interaction, binding, and individual many-body energies of water clusters. Importantly, molecular dynamics simulations carried out with MB-SCAN(DC) also reproduce the properties of liquid water, which thus demonstrates that MB-SCAN(DC) is effectively the first DFT-based model that correctly describes water from the gas to the liquid phase.

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