Accelerating the dynamics of infrequent events: Combining hyperdynamics and parallel replica dynamics to treat epitaxial layer growth

Voter, A F; Germann, T C

Title: Accelerating the dynamics of infrequent events: Combining hyperdynamics and parallel replica dynamics to treat epitaxial layer growth

Full Record
Other Related Research

Abstract

During the growth of a surface, morphology-controlling diffusion events occur over time scales that far exceed those accessible to molecular dynamics (MD) simulation. Kinetic Monte Carlo offers a way to reach much longer times, but suffers from the fact that the dynamics are correct only if all possible diffusion events are specified in advance. This is difficult due to the concerted nature of many of the recently discovered surface diffusion mechanisms and the complex configurations that arise during real growth. Here the authors describe two new approaches for this type of problem. The first, hyperdynamics, is an accelerated MD method, in which the trajectory is run on a modified potential energy surface and time is accumulated as a statistical property. Relative to regular MD, hyperdynamics can give computational gains of more than 10{sup 2}. The second method offers a way to parallelize the dynamics efficiently for systems too small for conventional parallel MD algorithms. Both methods exploit the infrequent-event nature of the diffusion process. After an introductory description of these methods, the authors present preliminary results from simulations combining the two approaches to reach near-millisecond time scales on systems relevant to epitaxial metal growth.

Authors:: Voter, A F; Germann, T C

Publication Date:: 1998-12-31

Research Org.:: Los Alamos National Lab., Theoretical Div., NM (United States)

Sponsoring Org.:: USDOE Office of Energy Research, Washington, DC (United States)

OSTI Identifier:: 304117

Report Number(s):: LA-UR-98-2136; CONF-980405-
ON: DE99000751; TRN: AHC29904%%193

DOE Contract Number:: W-7405-ENG-36

Resource Type:: Conference

Resource Relation:: Conference: Spring meeting of the Materials Research Society, San Francisco, CA (United States), 13-17 Apr 1998; Other Information: PBD: [1998]

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; METALS; EPITAXY; CALCULATION METHODS; DIFFUSION; CRYSTAL GROWTH; MOLECULAR DYNAMICS METHOD; TIME DEPENDENCE

Citation Formats


                    Voter, A F, and Germann, T C. Accelerating the dynamics of infrequent events: Combining hyperdynamics and parallel replica dynamics to treat epitaxial layer growth.  United States: N. p., 1998. 
        Web.

Copy to clipboard


                    Voter, A F, & Germann, T C. Accelerating the dynamics of infrequent events: Combining hyperdynamics and parallel replica dynamics to treat epitaxial layer growth.  United States.

Copy to clipboard


                    Voter, A F, and Germann, T C. 1998.  
        "Accelerating the dynamics of infrequent events: Combining hyperdynamics and parallel replica dynamics to treat epitaxial layer growth".  United States.  https://www.osti.gov/servlets/purl/304117.

Copy to clipboard


                    
@article{osti_304117,

  title        = {Accelerating the dynamics of infrequent events: Combining hyperdynamics and parallel replica dynamics to treat epitaxial layer growth},

  author       = {Voter, A F and Germann, T C},

  abstractNote = {During the growth of a surface, morphology-controlling diffusion events occur over time scales that far exceed those accessible to molecular dynamics (MD) simulation. Kinetic Monte Carlo offers a way to reach much longer times, but suffers from the fact that the dynamics are correct only if all possible diffusion events are specified in advance. This is difficult due to the concerted nature of many of the recently discovered surface diffusion mechanisms and the complex configurations that arise during real growth. Here the authors describe two new approaches for this type of problem. The first, hyperdynamics, is an accelerated MD method, in which the trajectory is run on a modified potential energy surface and time is accumulated as a statistical property. Relative to regular MD, hyperdynamics can give computational gains of more than 10{sup 2}. The second method offers a way to parallelize the dynamics efficiently for systems too small for conventional parallel MD algorithms. Both methods exploit the infrequent-event nature of the diffusion process. After an introductory description of these methods, the authors present preliminary results from simulations combining the two approaches to reach near-millisecond time scales on systems relevant to epitaxial metal growth.},

  doi          = {},

  url          = {https://www.osti.gov/biblio/304117},
  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {1998},

  month        = {12}

}

Copy to clipboard

Conference:

View Conference (1.65 MB)

Other availability

Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

Accelerating atomistic simulations of defect dynamics: Hyperdynamics, parallel replica dynamics, and temperature-accelerated dynamics

Conference Voter, A; Soerensen, M

Obtaining a good atomistic description of diffusion dynamics in materials remains a daunting task due to the time-scale limitations of the molecular dynamics method. The authors discuss new methods, derived from transition state theory, for accelerating molecular dynamics simulations of these infrequent-event processes. Two of these methods (hyperdynamics and parallel replica dynamics) have been presented previously, and are briefly reviewed here. The third, temperature-accelerated dynamics (TAD), is presented in detail. In TAD, the system temperature is raised to stimulate more rapid escape out of each potential basin, but attempted transitions are filtered to allow only those that would have occurredmore »« less
Parallel algorithms for hyperdynamics and local hyperdynamics

Journal Article Plimpton, Steven; Perez, Danny; Voter, Arthur - Journal of Chemical Physics

Hyperdynamics (HD) is a method for accelerating the timescale of standard molecular dynamics (MD). It can be used for simulations of systems with an energy potential landscape that is a collection of basins, separated by barriers, where transitions between basins are infrequent. HD enables the system to escape from a basin more quickly while enabling a statistically accurate renormalization of the simulation time, thus effectively boosting the timescale of the simulation. In [Kim, Perez, Voter, J Chem Phys, 139:144110, 2013)1, a local version of HD was formulated, which exploits the intrinsic locality characteristic typical of most systems to mitigate themore »« less
Cited by 7
https://doi.org/10.1063/5.0014448

Full Text Available
Decay of surface nanostructures via long-time-scale dynamics

Technical Report Voter, A; Stanciu, N

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors have developed a new approach for extending the time scale of molecular dynamics simulations. For infrequent-event systems, the category that includes most diffusive events in the solid phase, this hyperdynamics method can extend the simulation time by a few orders of magnitude compared to direct molecular dynamics. The trajectory is run on a potential surface that has been biased to raise the energy in the potential basins without affecting the transition state region. The method ismore »« less
https://doi.org/10.2172/674862

Full Text Available
Hyperdynamics: Accelerated Molecular Dynamics of Infrequent Events

Journal Article Voter, A - Physical Review Letters

I derive a general method for accelerating the molecular-dynamics (MD) simulation of infrequent events in solids. A bias potential ({Delta}V{sub b}) raises the energy in regions other than the transition states between potential basins. Transitions occur at an accelerated rate and the elapsed time becomes a statistical property of the system. {Delta}V{sub b} can be constructed without knowing the location of the transition states and implementation requires only first derivatives. I examine the diffusion mechanisms of a 10-atom Ag cluster on the Ag(111) surface using a 220 {mu}s hyper-MD simulation. {copyright} {ital 1997} {ital The American Physical Society}
https://doi.org/10.1103/PhysRevLett.78.3908
Parallel replica method for dynamics of infrequent events

Journal Article Voter, A - Physical Review, B: Condensed Matter

Although molecular-dynamics simulations can be parallelized effectively to treat large systems (10{sup 6}{endash}10{sup 8} atoms), to date the power of parallel computers has not been harnessed to make analogous gains in {ital time} scale. I present a simple approach for infrequent-event systems that extends the time scale with high parallel efficiency. Integrating a replica of the system independently on each processor until the first transition occurs gives the correct transition-time distribution, and hence the correct dynamics. I obtain {gt}90{percent} efficiency simulating Cu(100) surface vacancy diffusion on 15 processors. {copyright} {ital 1998} {ital The American Physical Society}
https://doi.org/10.1103/PhysRevB.57.R13985

Similar Records