Dislocation morphology and nucleation within compressed Si nanospheres: A molecular dynamics study

L. M. Hale, D. B. Zhang, X. Zhou, J. A. Zimmerman, N. R. Moody, T. Dumitrica, R. Ballarini, W. W. Gerberich

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Large scale molecular dynamics simulations of the compression of silicon nanospheres were performed with the Stillinger-Weber potential. Several defects were observed to cause the yielding, including dislocations, stacking faults and phase transformations. To better investigate dislocation interactions, spheres of increasing size comprised of up to one million atoms were simulated. The morphologies of the defects and the conditions under which they are formed are explored. A new and interesting route to dislocation formation is identified and examined in which perfect dislocations form on {1 1 0} planes as opposed to the expected {1 1 1} planes. The dislocations on {1 1 0} planes are observed to form through a pathway with an intermediate metastable state corresponding to a change in the atomic bonding. Density Functional based Tight Binding calculations reveal the feasibility of this pathway although the appearance of dislocations on the {1 1 0} plane in the molecular dynamics simulations is specific to the Stillinger-Weber potential.

Original languageEnglish (US)
Pages (from-to)280-286
Number of pages7
JournalComputational Materials Science
Volume54
Issue number1
DOIs
StatePublished - Mar 2012

Bibliographical note

Funding Information:
This work was partially supported (RB and LMH) by the National Science Foundation Grant NSF_CMMI 0800896 . One of us (WWG) would like to acknowledge additional support of the Air Force through an AOARD-08-4131 program dedicated to understanding plasticity and fracture in hard materials and the Abu Dhabi-Minnesota Institute for Research Excellence (ADMIRE); a partnership between the Petroleum Institute (PI) of Abu Dhabi and the Department of Chemical Engineering and Materials Science of the University of Minnesota. TD and WWG thank NSF Grand No. CMMI-1000415. Additionally, four of us (LMH, XZ, JAZ, and NMR) were supported by Sandia, Livermore. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

Keywords

  • Dislocation
  • Molecular dynamics
  • Nanoparticle
  • Silicon

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