Intersoliton hopping

The electronic band structure of a neutral polyacetylene is characterized by an empty band gap, like in other intrinsic semiconductors. Defect sites (solitons, polarons, bipolarons) can be regarded as electronic states within the band gap. The conduction in low-doped poly acetylene is attributed mainly to the transport of solitons within and between chains, as described by the intersoliton-hopping model (IHM) . Polarons and bipolarons are important charge carriers at higher doping levels and with polymers other than polyacetylene. 

It will be an interesting problem to analyze the intersoliton hopping mechanism assisted by a motion of the dopant molecule. We try to formulate here such an electron hopping process between two (CH), chains (Yamabe et al., 1984b), as illustrated in Fig. 14. 

A model found to correctly predict the steep increase in conductivity of P(Ac) on doping and dependence of P(Ac) on temperature is that proposed by Kivelson [180, 181]. In its essence, this "intersoliton hopping" model applied primarily to P(Ac) proposes isoenergetic hopping of electrons from a neutral soliton of one chain to a charged soliton at a neighboring chain via tunnelling. It is able to account well for... 

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