Material properties of low-dimensional charge-transfer salts: the temperature dependence of the direct current electrical conductivity in synthetic metals of the Kohn type

A Kubo-Mori projector formalism for one-phonon, one-electron (1ple) scattering processes has been employed to investigate the temperature dependence of the dc electrical conductivity, σ(T), in low-dimensional synthetic metals where remarkable mode softening is possible. The single-particle theory is applied to a number of model systems with small anisotropies in the conductivity but where particle hole symmetry on the Fermi surface leads nevertheless to flat portions. The latter are the structural (topologic) prerequisites for the development of staggered Kohn mode softening