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What is the momentum of an electron?

  1. Jul 30, 2012 #1
    I was learning about indirect band gap and it says that when the electron comes down from upper energy level to lower energy level it emits photon(which I can understand) but in order to conserve the momentum it emits phonons (which I couldn't understand).

    Can you please help me with this?

    Thanks a lot.
  2. jcsd
  3. Jul 30, 2012 #2
    Try wikipedia here:


    Note the diagrams near the top of the page.....

    I don't know much about phonon quasi particles except that they are associated with vibrating structures like lattices.....

    Is this your situation??.....read further along in the wiki article and note

    Last edited: Jul 30, 2012
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