Critical Size for Fracture during
Solid-Solid Phase Transformations
David Zaziski,Stephen Prilliman,Erik C. Scher,Maria Casula,Juanita Wickham,Simon M. Clark, andA. Paul Alivisatos*
Department of Chemistry, University of California, Berkeley, California 94720,
Materials Sciences Division, Lawrence Berkeley National Laboratory,
Berkeley, California 94720, Nanosys, Inc., 2625 Hanover Street,
Palo Alto, California 94304, and Advanced Light Source, Lawrence Berkeley
National Laboratory, Berkeley, California 94720
Received March 24, 2004
Abstract:
The study of nanoscale materials with well-controlled size and shape can be used to learn more about critical length scales for numerous
physical and chemical phenomena in solids and extended systems.1,2 Small nanocrystals (below 5-nm diameter) have been shown to exhibit
fully reversible single-domain structural phase transformations with large volume changes over multiple cycles. The same transformations in
extended solids are accompanied by irreversible domain formation.3-5 Here we investigate the crossover between these regimes by studying
a pressure-induced structural transformation in 4-nm-diameter nanorods varying in aspect ratio from 1 to 10. We find that above a critical
length the nanorods fracture at the moment of the structural transformation. This work demonstrates the use of simple, well-defined nanoscale
systems to examine fundamental structural phenomena found in extended solids.
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