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Is Einstein's relation D = ukT always true?

  1. Oct 14, 2015 #1
    I am trying to understand electron transport in 2D semiconductors. One question keeps lingering in my mind is whether the Einstein relation holds for these 2D materials. The only literature I can find is back to 1997 (http://arxiv.org/ftp/arxiv/papers/1004/1004.1717.pdf). The author proposed one situation that Einstein Relation may not hold: electron transport in fluid particles.
    Any thought about this is appreciated!
  2. jcsd
  3. Oct 19, 2015 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
  4. Oct 21, 2015 #3


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    The Einstein relation holds true for non-degenerate charged gas system. By non-degenerate I mean system obeying Boltzmann distribution, that is n~ exp(-eV/kT). Combine that with the flux equation J = -e⋅n⋅∇V - D∇n and, in equilibrium, J =0. That gives you the Einstein relation.
    If the system is degenerate (i.e. obeys Fermi-Dirac statistics), the relation may not hold true.
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