Dielectric constant of a dimerized interrupted strand model

Abstract

The static electronic polarizability has been calculated in a one-electron tight-binding approximation for dimerized linear chains of various lengths, L. When dimerization creates a Peierls gap that is comparable to or greater than the intrinsic level splitting, the electronic polarization is reduced and increases less rapidly with chain length than N2, the result obtained for a non-dimerized chain. One can infer, therefore, that an organic material composed of strands of such chains will exhibit a dielectric constant that increases with sample perfection or with average chain length. The dielectric constant is also shown to increase significantly with temperature at temperatures well below the half gap at the Fermi level. This reflects the relatively large amount of polarization carried by the states in the vicinity of the Fermi level for the dimerized chain. © 1976.