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Homework Help: Solid state physics energy, translation

  1. Dec 11, 2014 #1

    I'm having some trouble understanding why the energy changes here between the blue and red paths (see attached image), it's representing state of an electron in a square lattice crystal. Like mathematically I can see it because obviously plug and chugging the different values k in E(k) give different energies but the physics I'm completely lost on. My thinking was that the energy curves would be equal as everything should be.. periodic, I mean we're just in another '1st' Brillouin zone with the other point as a reference.

    Obviously it's not the case though unless maths started lying. What am I actually looking at with E(k - G), like what does the translation actually mean physically? We have all the possible states represented in the first Brillouin zone with the allowed k's there, so what am I looking at with k vectors outside the first Brillouin zone?

    Thanks in advance, having a hard time wrapping my head around reciprocal space. Not using the template as the question was "find the energies" which I have, I just can't interpret them.

    Attached Files:

    • ener.png
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  2. jcsd
  3. Dec 16, 2014 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
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