High-field electrical conductivity in disordered systems

The electric field dependence of the tunnelling probability between localized states in a disordered solid is presented. The dc conductivity has been determined as a function of the dimension d of the system. We find that, at high fields ( E U 106Vcm-1), the conductivity decreases with increasing field as ln † œ - E 1/2/ T, independently of the dimension of the system.