Method for long time scale simulations of solids: Application to crystal growth and dopant clustering

PDF Version Also Available for Download.

Description

An important challenge in theoretical chemistry is the time scale problem. Atomic motion can be simulated directly by integrating Newton's equations over a time scale of nanoseconds, but most interesting chemical reactions take place on a time scale of seconds. We have developed a methodology to bridge this time scale gap using harmonic transition state theory suitable for solid systems. Possible reactive events and their rates are found with a saddle point finding method called the dimer method. When enough events are found, a kinetic Monte Carlo algorithm is used to choose which event occurs so that the system's position ... continued below

Physical Description

5 p.

Creation Information

Henkelman, G. A. (Graeme A.); Uberuaga, B. P. (Blas Pedro) & Jónsson, Hannes, January 1, 2002.

Context

This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. More information about this article can be viewed below.

Who

People and organizations associated with either the creation of this article or its content.

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this article. Follow the links below to find similar items on the Digital Library.

Description

An important challenge in theoretical chemistry is the time scale problem. Atomic motion can be simulated directly by integrating Newton's equations over a time scale of nanoseconds, but most interesting chemical reactions take place on a time scale of seconds. We have developed a methodology to bridge this time scale gap using harmonic transition state theory suitable for solid systems. Possible reactive events and their rates are found with a saddle point finding method called the dimer method. When enough events are found, a kinetic Monte Carlo algorithm is used to choose which event occurs so that the system's position can be advanced in time. This technique has two major advantages over traditional kinetic Monte Carlo -- atoms do not have to map onto lattice sites for classification and kinetic events can be arbitrarily complicated. We have studied the homoepitaxial growth of aluminum and copper using an EAM potential at 80K with experimentally relevant deposition rates of monolayers per minute using a multiple time scale approach. Atomic deposition events are simulated directly with classical dynamics for several picoseconds until the incident energy has dissipated, and the long time between deposition events is simulated with the adaptive kinetic Monte Carlo method. Our simulations indicate that the Al( 100) surface grows much smoother then Cu( 100) at temperature between 0 and 80K due in part to long range multi atom processes which enable aluminum atoms to easily descend from atop islands. The high rate of such processes is due to their low activation energy, which is supported by density functional theory calculations, and the trend that processes involving more atoms tend to have larger prefactors and be favored by entropy. The scheme is efficient enough to model the evolution of systems with ab-initio forces as well, for which I will show an example of the breakup of dopant clusters in silicon.

Physical Description

5 p.

Source

  • Submitted to: Conference on stochastic and multiscale problems in the sciences, Dec. 2002, Princeton, NJ

Language

Item Type

Identifier

Unique identifying numbers for this article in the Digital Library or other systems.

  • Report No.: LA-UR-02-7575
  • Grant Number: none
  • Office of Scientific & Technical Information Report Number: 976483
  • Archival Resource Key: ark:/67531/metadc935471

Collections

This article is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

What responsibilities do I have when using this article?

When

Dates and time periods associated with this article.

Creation Date

  • January 1, 2002

Added to The UNT Digital Library

  • Nov. 13, 2016, 7:26 p.m.

Description Last Updated

  • Dec. 12, 2016, 6:04 p.m.

Usage Statistics

When was this article last used?

Yesterday: 0
Past 30 days: 0
Total Uses: 2

Interact With This Article

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Henkelman, G. A. (Graeme A.); Uberuaga, B. P. (Blas Pedro) & Jónsson, Hannes,. Method for long time scale simulations of solids: Application to crystal growth and dopant clustering, article, January 1, 2002; United States. (digital.library.unt.edu/ark:/67531/metadc935471/: accessed August 18, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.