Behavior of the thermopower in amorphous materials at the metal-insulator transition

We study the behavior of the thermal transport properties in three-dimensio nal disordered systems close to the metal-insulator transition within linea r response. Using a suitable form for the energy-dependent conductivity sig ma, we show that the value of the dynamical scaling exponent for noninterac ting disordered systems such as the Anderson model of localization can be r eproduced. Furthermore, the values of the thermopower S have the right orde r of magnitude close to the transition as compared to the experimental resu lts. A sign change in the thermoelectric power S - as is often observed in experiments - can also be modeled within the linear response formulation us ing modified experimental sigma data as input.