Thermodynamic density of states

Here, gr(( ) is a polarization-vector weighted density of states, closely related to the thermodynamic density of states or frequency distribution [see Equation (6)] of the sample in question. 

In this approximatiOTi, the Fermi—Dirac function is a unity step function at the Fermi level. Therefore, displacing the Fermi level by d p simply fills with carriers a slice of the DOS dn = g Ep)dEp. is also denoted a thermodynamic density of states [138]. 

---