Off-lattice Kinetic Monte Carlo simulations of strained hetero-epitaxial growth

Michael Biehl, Rijksuniversiteit Groningen

An off-lattice Kinetic Monte Carlo (KCM) method will be introduced, which can be applied in the context of strained heteroepitaxial crystal growth. Earlier applications of the method will be summarized briefly. They concern the formation of misfit dislocations at a critical film thickness and the emergence of self-organized islands or dots in the so-called Stranski-Krastanov growth mode.

Most recent studies were motivated by the experimental investigation of ternary material sytems, e.g. CoAg/Ru(0001) and FeAg/Mo(110). In such an AB/S system, the co-deposition of adsorbate materials A and B on an appropriate substrate S can lead to a highly non-trivial composition profile in the first monolayer already. If the lattice misfits of A and B with respect to S differ in sign, one observes a variety of remarkable structures. A particularly interesting example is the dendritic growth of A/B islands with a stripe substructure on the nanometer scale. Such structures might be of interest for the development of, for example, novel magnetic storage devices.

Our KMC simulations show that both, the misfit induced strain and kinetic seggregation effects, must be taken into account explicitly for an explanation of experimental observations.