INTERCHAIN POLARON TRANSPORT IN TRANSPOLYACETYLENE

The critical factor determining whether polaron motion is band-like, where the deformation or phonon cloud essentially moves with the polaron, or hopping is the bandwidth. We have recalculated the bandwidth for polaron motion perpendicular to the chains in polyacetylene, including a factor representing the change in the overlap of electrons in the valence band when the polaron moves onto or off a chain. The result is that the motion is hopping at all but extremely low temperatures. Within the range of our calculation, the temperature dependence that we find for the hopping mobility agrees well with that measured for photoconductivity transverse to the chains.