AVS 45th International Symposium
    Surface Science Division Friday Sessions
       Session SS1-FrM

Paper SS1-FrM4
Interaction of Dislocations on Strained Metal Films

Friday, November 6, 1998, 9:20 am, Room 308

Session: Surface Structure and Strain
Presenter: J. de la Figuera, Sandia National Laboratories
Authors: J. de la Figuera, Sandia National Laboratories
K. Pohl, Sandia National Laboratories
A.K. Schmid, Sandia National Laboratories
N.C. Bartelt, Sandia National Laboratories
R.Q. Hwang, Sandia National Laboratories
Correspondent: Click to Email
Misfit dislocations appear in thin film growth to relieve the mismatch between substrate and film. A general family of dislocation networks has been found on substrates with triangular symmetry such as Pt(111), Ru(0001) and Au(111). A common uncertainty in understanding the observed surface structures is the stacking sequence followed by each adlayer, information that is relatively simple to extract for single layer films but requires more detailed information in multilayer films. Another recurrent question is the role played by the substrate in the network structure and periodicity, as some networks are attributed to ``long range elastic effects'' on one hand,@footnote 1@ but in other cases can be explained disregarding those effects.@footnote 2@ Cu on Ru(0001) presents a variety of different networks as a function of film thickness,@footnote 3@ and can be considered a testbed for the study of misfit dislocations on a triangular substrate. But even in this case, most of the studies have not dealt in detail with the stacking sequence in the first few layers (other than by assuming that the dislocations observed are present at the interface between the substrate and the Ru film). We will discuss how one can use STM to unambiguously determine the stacking sequences in films thicker than one monolayer. We then proceed to determine the range of dislocation interactions. On the basis of these measurements it is possible to compare the model of long ranged dislocation interactions due to Ru substrate relaxations versus local exponentially decaying interactions between dislocations due to 2-D distortions within the Cu film. @FootnoteText@ @footnote 1@S. Narasimhan and D. Vanderbilt, Phys. Rev. Lett. 69, 1564 (1992). @footnote 2@J. C. Hamilton and S. M. Foiles, Phys. Rev. Lett. 75, 882 (1995). @footnote 3@C. Günther et al, Phys. Rev. Lett. 74, 754 (1995).