An extended model for the mobility edge carrier transport

Abstract The carrier transport property near the mobility edge is discussed on the basis of the renormalization group equation, in which the inelastic scattering effect is phenomenologically taken into account. The Q-function, Q=(e/kB)S(T)+lnσ(T), where S(T) denotes the thermopower and σ(T) the conductivity, is found to be virtually proportional to the reciprocal temperature, reproducing the experimentally observed Q-function behavior as the classical long-ranged potential fluctuation model does. We briefly argue implications from the temperature dependence of the Q-function for the band edge carrier mean free path as well as the width of the localized states.