DENSITY OF STATES FOR AN ELECTRONIC SPECTRUM WITH A FORBIDDEN BAND

Abstract

Quasi-one-dimensional organic crystals with high electrical conductivity at room temperature are prospect materials for thermoelectric applications. However, usually at some low temperature these materials manifest metal-dielectric transition of Peierls type. The aim of this paper is to calculate the density of electronic states and to show that the metal-dielectric transition is determined by the appearance of a forbidden band in the electronic spectrum exactly above the Fermi energy. While decreasing the temperature T, this forbidden band becomes larger and at some T prevails the value of k0T, where k0 is the Boltzmann constant and the carriers cannot be exited across the forbidden band. This temperature corresponds to metal-dielectric transition.