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What is the meaning of k in E(k) diagram?

  1. Aug 10, 2011 #1
    hello :) ,

    like I said in the title of this topic I am confused about physical interpretation of physical quantity ˝k˝. I came to this problem while doing the first chapter of book in semiconductor physics, where authors simply define some value (parameter) ˝k˝ thanks to solution of some equation, but they didn't give any meaning for ˝k˝. Only what they said is that ˝k˝ can be real or complex.

    First I thought it can be understood through wavelength of electron (particle), but since it can be complex I'm not sure. Perhaps only Re{k} corresponds to wavelength?..

    So, if anybody can help, please be my guest :)..
     
  2. jcsd
  3. Aug 10, 2011 #2

    ZapperZ

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    k is the wavenumber, or more importantly, related to the momentum (crystal momentum) in the E(k) dispersion diagram.

    p=hbar*k

    Zz.
     
  4. Aug 10, 2011 #3
    Ok, thanks :) .

    Just to ask one more thing. I'm not so sure what energy we are talking about when we say E(k)? Is it kinetic energy or potential or maybe whole energy of electron (Ek+U)?
    I suppose that it is kinetic part since it is related to the momentum of electron..
     
  5. Aug 10, 2011 #4

    ZapperZ

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    It's kinetic energy.

    Zz.
     
  6. Aug 12, 2011 #5
    E(k)=(hbar*k)^2/(2m)+Vo

    In the E(k) diagrams (dispertion curve) E can be considered as the kinetic energy only, but the zero energy value corresponds to the potential energy Vo, so, it's not actually zero.
     
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