Thermoelectric Transport Properties in Disordered Systems Near the Anderson Transition

We study the thermoelectric transport properties in the three-dimensional Anderson model of localization near the metal-insulator transition [MIT]. In particular, we investigate the dependence of the thermoelectric power S, the thermal conductivity K, and the Lorenz number L_0 on temperature T. We first calculate the T dependence of the chemical potential from the number density of electrons at the MIT using averaged density of state obtained by diagonalization. Without any additional approximation, we determine from the chemical potential the behavior of S, K and L_0 at low T as the MIT is approached. We find that the d.c. conductivity and K decrease to zero at the MIT as T -> 0 and show that S does not diverge. Both S and L_0 become temperature independent at the MIT and depend only on the critical behavior of the conductivity.