Direct atomistic simulation of brittle-to-ductile transition in silicon single crystals

Dipanjan Sen, Alan Cohen, Aidan P. Thompson, Adri C.T. Van Duin, William A. Goddard, Markus J. Buehler

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

Abstract

Silicon is an important material not only for semiconductor applications, but also for the development of novel bioinspired and biomimicking materials and structures or drug delivery systems in the context of nanomedicine. For these applications, a thorough understanding of the fracture behavior of the material is critical. In this paper we address this issue by investigating a fundamental issue of the mechanical properties of silicon, its behavior under extreme mechanical loading. Earlier experimental work has shown that at low temperatures, silicon is a brittle material that fractures catastrophically like glass once the applied load exceeds a threshold value. At elevated temperatures, however, the behavior of silicon is ductile. This brittle-to-ductile transition (BDT) has been observed in many experimental studies of single crystals of silicon. However, the mechanisms that lead to this change in behavior remain questionable, and the atomic-scale phenomena are unknown. Here we report for the first time the direct atomistic simulation of the nucleation of dislocations from a crack tip in silicon only due to an increase of the temperature, using large-scale atomistic simulation with the first principles based ReaxFF force field. By raising the temperature in a computational experiment with otherwise identical boundary conditions, we show that the material response changes from brittle cracking to emission of a dislocation at the crack tip, representing evidence for a potential mechanisms of dislocation mediated ductility in silicon.

Original languageEnglish (US)
Title of host publicationIntegrated Miniaturized Materials - From Self-Assembly to Device Integration
PublisherMaterials Research Society
Pages195-200
Number of pages6
ISBN (Print)9781605112497
DOIs
StatePublished - 2010

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1272
ISSN (Print)0272-9172

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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