Defect Induced Amortization in Silicon: A Tight Binding Molecular Dynamics Simulation

1993 ◽  
Vol 316 ◽  
Author(s):  
D. Maric ◽  
L. Colombo
Keyword(s):  
Molecular Dynamics ◽  
Electronic Properties ◽  
Structural Properties ◽  
Crystalline Silicon ◽  
Ion Beam ◽  
Tight Binding ◽  
Dynamics Simulation ◽  
Rapid Quench ◽  
Amorphous Network ◽  
Different Temperatures

ABSTRACTWe present an investigation on the amorphization process of crystalline silicon induced by ion beam bombardment by simulating the insertion of self-interstitials at different temperatures. The simulation is carried out by tight-binding molecular dynamics which allows for a detailed characterization of the chemical bonding and electronic properties of the irradiated samples. The irradiation process consists of two steps: (i) insertion of defects at a constant rate; (ii) annealing of the sample and observation of its structural properties. Thanks to the large size of the simulation cell (up to 276 atoms) we can characterize the amorphous network both on the short-range and medium-range length scale. Electronic properties are investigated as well and their evolution is monitored during the insertion process. Finally, we present a thorough comparison of the structural properties of the irradiated sample with amorphous silicon as obtained by rapid quench from the melt.

Defect Induced Amortization in Silicon: A Tight Binding Molecular Dynamics Simulation

1993 ◽  
Vol 321 ◽  
Author(s):  
D. Maric ◽  
L. Colombo
Keyword(s):  
Molecular Dynamics ◽  
Electronic Properties ◽  
Structural Properties ◽  
Crystalline Silicon ◽  
Ion Beam ◽  
Tight Binding ◽  
Dynamics Simulation ◽  
Rapid Quench ◽  
Amorphous Network ◽  
Different Temperatures

ABSTRACTWe present an investigation on the amorphization process of crystalline silicon induced by ion beam bombardment by simulating the insertion of self-interstitials at different temperatures. The simulation is carried out by tight-binding molecular dynamics which allows for a detailed characterization of the chemical bonding and electronic properties of the irradiated samples. The irradiation process consists of two steps: (i) insertion of defects at a constant rate; (ii) annealing of the sample and observation of its structural properties. Thanks to the large size of the simulation cell (up to 276 atoms) we can characterize the amorphous network both on the short-range and Medium-range length scale. Electronic properties are investigated as well and their evolution is monitored during the insertion process. Finally, we present a thorough comparison of the structural properties of the irradiated sample with amorphous silicon as obtained by rapid quench from the Melt.

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

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.

scholarly journals Molecular dynamics study of diffusion of xenon in water at different temperatures

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
Niraj Kumar ◽  
Narayan Prasad Adhikari
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Structural Properties ◽  
The Self ◽  
Dynamics Simulation ◽  
Velocity Autocorrelation Function ◽  
Arrhenius Behavior ◽  
Self Diffusion ◽  
Different Temperatures ◽  
Self Diffusion Coefficient

Molecular Dynamics simulation was performed using 2 xenon atoms as solute and 300 water molecules as solvent. We have studied the structural properties as well as transport property. As structural properties, we have determined the radial distribution function (RDF) of xenon-xenon, xenon-water, and water-water interactions. Study of RDF of xenon-xenon and oxygen-oxygen interactions of water shows that there is hydrophobic behavior of xenon in the presence of water. We have studied the self diffusion coefficient of xenon, water, and mutual diffusion coefficients of xenon in water. The self diffusion coefficient of xenon was estimated using both mean-squared displacement (MSD) and velocity autocorrelation function (VACF), while only MSD was used for water. The temperature dependence of the diffusion coefficient of xenon and water were found to follow the Arrhenius behavior. The activation energies obtained are 12.156 KJ/mole with MSD and 14.617 KJ/mole with VACF in the temperature range taken in this study.

A Tight-Binding Molecular Dynamics Simulation of the Melting and Solidification of Silicon

1992 ◽  
Vol 291 ◽  
Author(s):  
Andrew Horsfield ◽  
Paulette Clancy
Keyword(s):  
Molecular Dynamics ◽  
Electrical Conductivity ◽  
Crystalline Silicon ◽  
Pair Correlation ◽  
Tight Binding ◽  
Diffusion Constant ◽  
Low Frequency ◽  
Dynamics Simulation ◽  
Three Body ◽  
Body Energy

ABSTRACTThe melting of crystalline silicon and the cooling of liquid silicon are investigated using Molecular Dynamics. Both the Stillinger-Weber (SW) potential and the Tight-Binding Bond Model are used to calculate the forces. The electrical properties are investigated using an empirical pseudopotential method with a plane wave basis. The melting point of the solid is found to be about 2300K. The dependency of this temperature with cell size is investigated. On cooling, there are changes in some of the properties of the liquid: the energy per particle decreases, the diffusion constant decreases, and the low frequency electrical conductivity decreases slightly as the temperature decreases. Between 1180K and 980K the liquid undergoes a transition to a glassy phase. There are large changes in the pair correlation function, the SW three-body energy distribution, the diffusion constant, the density of electron single particle states and the electrical conductivity. All of these changes are consistent with increased tetrahedral bonding.

Computer Simulation of Thermal Annealing Effects on Self Implanted Silicon

1994 ◽  
Vol 373 ◽  
Author(s):  
G. DE Sandre ◽  
L. Colombo ◽  
D. Maric
Keyword(s):  
Molecular Dynamics ◽  
Thermal Annealing ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Tight Binding ◽  
Defect Distribution ◽  
Amorphous Network ◽  
Different Temperatures ◽  
Annealing Effects

AbstractWe investigate the effects of thermal annealing on the structural, elastic and electronic properties of self implanted silicon by tight binding molecular dynamics. The irradiated samples, after a careful relaxation at room temperature, are annealed at different temperatures and for different times and, finally, their properties are carefully monitored during constant temperature simulations. We further provide a characterization of the chemical bonding in the amorphous network and show the evolution of the point defect distribution against maximum annealing temperature.

scholarly journals Tight-Binding Molecular Dynamics Simulations on Point Defects Diffusion and Interactions in Crystalline Silicon

1995 ◽  
Vol 396 ◽  
Author(s):  
M. tang ◽  
L. colombo ◽  
T. Diaz De La Rubia
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Point Defects ◽  
Crystalline Silicon ◽  
Tight Binding ◽  
Diffusion Path ◽  
Binding Energies ◽  
Defect Clusters ◽  
Dynamics Simulations

AbstractTight-binding molecular dynamics (TBMD) simulations are performed (i) to evaluate the formation and binding energies of point defects and defect clusters, (ii) to compute the diffusivity of self-interstitial and vacancy in crystalline silicon, and (iii) to characterize the diffusion path and mechanism at the atomistic level. In addition, the interaction between individual defects and their clustering is investigated.

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