Atomistic study of crack-tip cleavage to dislocation emission transition in silicon single crystals

At low temperatures silicon is a brittle material that shatters catastrophically, whereas at elevated temperatures, the behavior of silicon changes drastically over a narrow temperature range and suddenly becomes ductile. This brittle-to-ductile transition has been observed in experimental studies,...

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Bibliographic Details
Published in:Physical review letters Vol. 104; no. 23; p. 235502
Main Authors: Sen, Dipanjan, Thaulow, Christian, Schieffer, Stella V, Cohen, Alan, Buehler, Markus J
Format: Journal Article
Language:English
Published: United States 11-06-2010
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Summary:At low temperatures silicon is a brittle material that shatters catastrophically, whereas at elevated temperatures, the behavior of silicon changes drastically over a narrow temperature range and suddenly becomes ductile. This brittle-to-ductile transition has been observed in experimental studies, yet its fundamental mechanisms remain unknown. Here we report an atomistic-level study of a fundamental event in this transition, the change from brittle cleavage fracture to dislocation emission at crack tips, using the first principles based reactive force field. By solely raising the temperature, we observe an abrupt change from brittle cracking to dislocation emission from a crack within a ≈10  K temperature interval.
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ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.104.235502