Tu Yuhai, Tersoff J
IBM Research Division, T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598, USA.
Phys Rev Lett. 2007 Mar 2;98(9):096103. doi: 10.1103/PhysRevLett.98.096103. Epub 2007 Feb 27.
During heteroepitaxy, misfit strain causes nanoscale islands to form spontaneously, as "self-assembled quantum dots." The growth and evolution of these islands are remarkably complex. We show that continuum modeling reproduces and explains many of the surprising phenomena observed experimentally. The free energy is reduced by both morphological change and alloy intermixing. However, because diffusion occurs only at the surface, the morphological and compositional evolution are strongly coupled. This leads to a complex dynamical response to the rather simple thermodynamic driving forces.
在异质外延过程中，失配应变会导致纳米级岛状结构自发形成，即“自组装量子点”。这些岛状结构的生长和演化极为复杂。我们表明，连续介质模型能够再现并解释许多实验中观察到的惊人现象。形态变化和合金混合都会降低自由能。然而，由于扩散仅发生在表面，形态和成分演化紧密耦合。这导致了对相当简单的热力学驱动力产生复杂的动力学响应。
