Critical behaviour of thermopower and conductivity at the metal-insulator transition in high-mobility Si-MOSFETs

This paper reports thermopower and conductivity measurements through the me tal-insulator transition for two-dimensional electron gases in high-mobilit y Si-MOSFETs, At low temperatures both thermopower and conductivity show cr itical behaviour as functions of the electron density. When approaching the critical density from the metallic side the diffusion thermopower appears to diverge and the conductivity vanishes. On the insulating side the thermo power shows an upturn with decreasing temperature. These features have much in common with those expected for an Anderson transition.