Fermi energy statistical shift

The temperature dependence of E is referred to as the statistical shift and is present whenever the Fermi energy lies within an asymmetrical density of states distribution. The position of E is determined from the electron concentration, n, by... 

Conductivity data for n-type and p-type samples above the equilibration temperature are shown in Fig. 7.4 and similar data are in Fig. 5.2. The conductivity is activated with a prefactor of 100-200 cm for both doping types and the activation energy is 0.3-0.4 eV in n-type material and 0.4-0.6 eV in p-type. In the thermal equilibrium regime, the Fermi energy is pinned by the defect and dopant states and consequently the statistical shift is small, as is discussed in Section 6.2.2. Yp may be calculated from a numerical... 

The statistical shift of E and the possible temperature dependence of the conduction energy, which complicate the analysis of the conductivity, also enter into the thermopower equations. However, o(J) and S T) can be combined into a function Q T) which eliminates the statistical shift, since the Fermi energy position drops out of the combined expression (Beyer and Overhof 1979),... 

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