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.
|Original language||English (US)|
|Number of pages||5|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Jan 15 2002|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics