From some literature review I have found that the Seebeck coefficient is directly proportional to the slope of Density of States ( or Derivative of DOS). But, I couldn't understand how these two are related. Can someone please explain the physical meaning of this?
Reference paper:
Strain Effects To Optimize Thermoelectric Properties of Doped Bi2O2Se via Tran-Blaha Modified Becke-Johnson Density Functional Theory
Guo, Donglin, Chenguo Hu, Yi Xi, and Kaiyou Zhang. "Strain effects to optimize thermoelectric properties of doped Bi2O2Se via Tran–Blaha modified Becke–Johnson density functional theory." The Journal of Physical Chemistry C 117, no. 41 (2013): 21597-21602.
in every case when different metals or semiconductor materials are joined together, a Seebeck Effect at any scale is observed on the pair of materials.
The Seebeck coefficient depends on an imbalance between the density of electrons above the Fermi level and electrons below it. If the Density of States is rather flat (slope is small) the imbalance is small and the Seebeck is small. If the Density of States changes sharply near the Fermi level (large slope), the imbalance is large and so is the Seebeck. Note that the sign of the slope (positive or negative) near the Fermi level also determines if the Seebeck is "n-type or p-type". That is why some metals have a "p-type" Seebeck coefficient.
Look for the Boltzmann formulation of the Seebeck coefficient and the interpretation of the Fermi window (df/dE). I have attached my dissertation, read section 2.1.4.2, hopefully that will clear it up a little.
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