next up previous contents
Next: Phase slips Up: Systems and Models Previous: Vortex lattices and Wigner

Topological defects

 

A major difference between elastic manifolds and elastic media is that in the latter, we must account for the possibility of topological defects. In the manifolds, the elastic fields were simply generalized ``heights'' of an interface or line, and as such had well-defined meanings as real-space coordinates. In an elastic medium, the displacements tex2html_wrap_inline2762 are only defined relative to some background configuration, or in the continuum limit in terms of their effect upon the density. We should therefore allow for the possibility of defects, e.g. vacancies, interstitials, and dislocations in the lattice. These have the effect of making tex2html_wrap_inline2762 multivalued. Configurations of the medium which include topological defects are said to involve plastic deformations, as opposed to purely elastic deformations when they are not present.





Leon Balents
Thu May 30 08:21:44 PDT 1996