The effect of electron state hybridization on the frequency dependence of hopping conductivity in disordered systems

The effect of electron state hybridization on phononless hopping conductivity in a disordered system of point localization centers in the intermediate frequency range corresponding to electron transitions to distant centers is discussed. When the basis of the atom-type localized functions is applied, with the hybridization of the wave functions of the distant centers not being taken into account, the frequency dependence of phononless conductivity is shown to be superlinear and monotonic in a wide frequency range. In this case, the kink in the vicinity of a crossover from a linear to a quadratic frequency dependence of the conductivity turns out to be sharper as distinct from the standard theory.