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Title: Supersonic Dislocation Bursts in Silicon

Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolution we successfully predict a dislocation density of 1.5 x 10(12) cm(-2) within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon.
Authors:
 [1] ;  [1] ;  [2] ;  [1]
  1. Univ. of California, San Diego, CA (United States). Materials Science and Engineering Program
  2. Universidad Nacional de Cuyo, Mendoza (Argentina), Ciencias Exactas y Naturales; CONICET, Mendoza (Argentina)
Publication Date:
OSTI Identifier:
1280869
Grant/Contract Number:
NA0002080
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Univ. of California, San Diego, CA (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA) (SSAP); US DOE office of Advanced Scientific Computing Research (ASCR); UC Research Laboratories Grant
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE shock compression; molecular-dynamics; strain-rate; computer; sound