INSULATOR-TO-METAL TRANSITION DRIVEN BY CLUSTERING OF SOLITONS IN POLYACETYLENE

It's believed that the simple Su-Schrieffer-Heeger Hamiltonian can not predict the insulator to metal transition of trans-polyacetylene (t-P A). The soliton lattice configuration at a doping level y=6% still has a semiconductor gap. Disordered distributions of solitons close the g ap, but the electronic states around the Fermi energy are localized. H owever, within the same framework, it is possible to show that a clust er of solitons can produce dramatic changes in the electronic structur e, allowing an insulator-to-metal transition.