Non-metallic transport in molecular solids versus dimensionality

Path integral techniques and the Green's function formalism are applied to study the time- and temperature-dependent scattering of a polaronic quasiparticle using a local anharmonic potential in a bath of diatomic molecules. The electrical resistivity has been computed for any molecular lattice dimensionality for different values of the electron-phonon coupling and intermolecular forces. A broad resistivity peak with non-metallic behaviour at temperatures larger than similar or equal to 100 K is predicted by the model for sufficiently strong polaron-local potential coupling strengths. This peculiar behaviour, ascribed to purely structural effects, is favoured for low dimensionality.