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Umklapp process

  1. Oct 30, 2013 #1
    This occur when two phonons interact and the sum of their momenta add to a new wavevector outside the new Brillioun zone. The resulting wavevector is then mapped back into the Brillioun zone by subtraction of a suitable reciprocal lattice vector.
    I don't think I understand the physics in all of this. I understand the idea but what is physically going on in this process and where does the leftover momentum go?
  2. jcsd
  3. Oct 30, 2013 #2


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  4. Oct 31, 2013 #3


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    Well, of course also real momentum is conserved. It is taken up completely by the lattice.
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