Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Expanding atomic displacements in terms of all lattice wave modes?

  1. Oct 31, 2012 #1
    I find the expression:

    "In general, one can expand the atomic displacements in terms of all the lattice wave
    modes (resembles a Fourier series expansion)"


    But I have not found the expression in any other literature. (In fact, some literature, like P.Y. Yu and M. Cardona: Fundamentals of Semiconductors, a long wavelength limitation seems to have been imposed.) Is the above-cited expression correct (in 3D lattice)?

    Thank for your assistance.
    Last edited: Oct 31, 2012
  2. jcsd
  3. Oct 31, 2012 #2


    User Avatar
    Science Advisor

    Yes, that's true. Should be explained in any book on solid state theory.
  4. Oct 31, 2012 #3
    Have you ever done normal mode decomposition of a system of coupled oscillators? This is the same, except that the system is infinite, but periodic boundary conditions are imposed.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook