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Phys. Rev. B 65, 035401 (2001) [5 pages]

Dynamics of dislocations and surface instabilities in misfitting heteroepitaxial films

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Mikko Haataja1, Judith Müller2, A. D. Rutenberg3, and Martin Grant1
1Centre for the Physics of Materials, Department of Physics, McGill University, Rutherford Building, 3600 rue University, Montréal, Québec H3A 2T8, Canada
2Instituut-Lorentz for Theoretical Physics, University of Leiden, P.O. Box 9506, NL-2300 RA Leiden, The Netherlands
3Department of Physics, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada

Received 6 June 2001; published 13 December 2001

We introduce a continuum model of elasticity in a nonequilibrium multiphase system—including smooth and singular strains, as well as their coupling to free surfaces—and apply it to the dynamics of misfitting heteroepitaxial films. Above a critical thickness, defects relieve strain, competing with an instability at the interface. Depending on their mobility, defects can screen stress by building up at large-curvature groove tips, leading to high ductility, or be “outrun” by the tips, leading to brittleness. Hence we find a nonequilibrium brittle to ductile transition.

© 2001 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.65.035401
DOI:
10.1103/PhysRevB.65.035401
PACS:
62.20.Fe, 64.60.My, 68.55.-a
 
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