1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Kittel chapter 7

  1. Feb 29, 2008 #1
    1. The problem statement, all variables and given/known data
    This question refers to Kittel's solid-state physics book.

    I am confused about why you get a set of equations for the central equation. They say that psi_k could equally well be labeled by psi_{k+G}, so isn't the central equation going to be exactly the same when you change k to k+G, except maybe with the index shifted? So, what is the point of writing all those equation that are just cyclic permutations of one another?

    Also, can someone explain why they say, in the "Approximate Solution Near a Zone Boundary," that they only retain coefficients in the central equation that contain both coefficieints C(.5G) and C(-.5G)? How do they know that there are no other important coefficients? It seems like they not only use only those two equations, but they set all of the other coefficients to 0 in the two equations that they do use, right? How is that justified?

    2. Relevant equations



    3. The attempt at a solution
     
    Last edited: Feb 29, 2008
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you help with the solution or looking for help too?



Similar Discussions: Kittel chapter 7
  1. Zwiebach chapter 9-12 (Replies: 0)

Loading...