On the conduction mechanism in dielectrics

It is important to know if and to what extent the energy band model can be used in the case of dielectric materials. Using isothermal and non isothermal measurements with direct current and for triangular symmetric signals we tried to solve two problems: (i) the existence of the barrier potential at the contact between a metal and a dielectric; (ii) the resemblance and the differences between the displacement current and the so called conduction current in a dielectric. The answers to these two problems are important in deciding if the charge transport mechanism in dielectrics takes place by carrier movement in extended states or by carrier hopping between localized states