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Cdw sdw2

  1. Jun 14, 2012 #1
    why cdw occurs at low dimensional solids with anisotropic fermi surfaces that have prominent nesting vectors?/
    what it means : cdws are also common at the surface of solids???????where they are more commonly called surface reconstruction or dimerization .
    PLZ tell me about two dimensional Fermi surface? thanks so muchhhhhhhhhh
     
    Last edited: Jun 14, 2012
  2. jcsd
  3. Jun 15, 2012 #2
    A surface reconstruction is the re-arrangement of the last or few last layers of atoms at the surface of a single crystal. In general this is due to the missing neighbors at the surface.

    http://en.wikipedia.org/wiki/Surface_reconstruction

    I guess you could view surface reconstructions as special cases of CDW (after all atoms get displaced), but I suspect that the underlying physics is quite different. Surface reconstructions tend to be commensurate.

    Note that a "conventional" CDW is a bulk phenomenom, and that the CDW extends perpendicular to the propagation wave vector.

    Nesting occurs when sections of the Fermi surface are parallel to each other, i.e. when there is a reciprocal space vector that can transfer an electron from one part of the Fermi surface to another over some non-zero area of the Fermi surface. This creates an instability in the electronic system that can result in the formation of a modulated state such as CDW or SDW. The modulation wave vector is the reciprocal space vector that links the two parts of the Fermi surface.
     
    Last edited: Jun 15, 2012
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