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Homework Help: Electron - Phonon scattering, deriving the contribution to

  1. Apr 17, 2015 #1
    ... electron transport.

    1. The problem statement, all variables and given/known data

    Electron - Phonon scattering, derive the contribution to electron transport.

    2. Relevant equations

    3. The attempt at a solution
    Am I being REALLY stupid here, I can't see how the equation matches the triangle.


    If you resolve KF' doesnt KF' cos theta= KF

    The only thing I can think is that it's an approximation and delta KF is very small?
    Thanks for any help
  2. jcsd
  3. Apr 17, 2015 #2


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    Yes, I think you're right about ΔKF needing to be small. Also, I think φ needs to be small enough so that cos(φ) ≈ 1 , while (1 - cos(φ) ) can't be ignored.

    It looks to me like ΔKF is just a difference in magnitudes of the vectors and not the magnitude of the vector difference.
  4. Apr 19, 2015 #3
    Thanks very muvh for the reply.
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