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Phonon drag

  1. Aug 27, 2008 #1

    NJV

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    From Wikipedia:
    "Phonons are not always in local thermal equilibrium; they move along the thermal gradient. They lose momentum by interacting with electrons (or other carriers) and imperfections in the crystal. If the phonon-electron interaction is predominant, the phonons will tend to push the electrons to one end of the material, losing momentum in the process."

    Along the thermal gradient? That'd mean the current would run from cold to warm?
     
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  3. Aug 27, 2008 #2

    Gokul43201

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    They are not being very careful with the choice of words. "Against" would be accurate. You should edit it.

    Incidentally, in a material where the majority carriers are electrons, the phonon drag current will run from cold to warm (since the current direction is opposite the drift velocity for negative charges).
     
  4. Aug 27, 2008 #3

    NJV

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    Thank you very much. :)

    Ah yes, just that idiot convention based on the 19th century mistake that electrons had positive charge, you mean? Alright, thanks for pointing that out.
     
  5. Aug 27, 2008 #4

    Gokul43201

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    Just out of curiosity, is there a specific reason you were reading a wiki on phonon drag?
     
  6. Aug 27, 2008 #5

    NJV

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    I am often very curious, so it can occur that when I'm searching for the answer to on question I end up in a chain reaction of questions. I was writing in a sci-fi novel and needed particulars on how one could store heat, to cool overheated brain cells through nanorobots. One thing leads to another; first I searched for information on volumetric heat capacity, on erbium-alloy based heat exchangers, on magnetic refrigeration, on the magnetocaloric effect and finally on thermoelectricity and the Seebeck effect. I used a combination of some of these phenomena in my sci-fi technology, which would, admittedly, probably be as impracticable as an airplane without stabilizer, but at least it sounds more plausible now I have some technical backup.

    Either how, writing science fiction can be very stimulating to one's curiosity.

    And why I was reading a wiki, well, I know Wikipedia's not a very good source for physics, but it's by far the most concise I know. If you know any better sites for physics, I'd be thankful if you could share them.
     
  7. Aug 27, 2008 #6

    Gokul43201

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    I was going to say that you probably shouldn't use wikipedia as a final source if this is for college/grad school. Good luck with the book.
     
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