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Homework Help: Effective mass question

  1. Feb 25, 2007 #1
    1. The problem statement, all variables and given/known data

    Calculate the effective mass for a free electron.

    2. Relevant equations


    3. The attempt at a solution

    I know the above equation comes from, in the case of the free electron dispersion relation, 1632e523513112a5ba15209fd3e8de9b.png .

    However i'm not at all sure how to go about calculating it for a free electron, given that the two formulae are basically one in the same...
  2. jcsd
  3. Feb 25, 2007 #2


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    Staff Emeritus
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    Gold Member

    Note the following minor correction: the free electron dispersion relation is [itex] \epsilon = \hbar ^2 k^2 /2m_e [/itex]. What happens when you plug this into the expression for the effective mass?
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