Soliton excitations and polarons in polyacetylene

Abstract

We study the interaction between two solitons in an infinite chain of ${\left(\mathrm{CH}\right)}_x$, with the use of a recursive Green's-function method which allows the exact determination of the density of states and the energy of the system. The positions of the defect-induced levels in the band gap as well as the interaction energies of two solitons have been determined according to their configurations and their distance. It is then shown that the attractive interaction between a charged and a neutral soliton leads to a polaron bound state whose energy is about 0.64 eV. The stability of this polaron upon doping is then examined.