Umklapp process

  • Thread starter aaaa202
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  • #1
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Main Question or Discussion Point

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?
 

Answers and Replies

  • #3
DrDu
Science Advisor
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Well, of course also real momentum is conserved. It is taken up completely by the lattice.
 

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