Disorder-induced neutral solitons in degenerate ground state polymers

Submitted to: Synth. Met. Abstract: In this letter, we study the effects of weak off-diagonal disorder on conjugated polymers with a doubly degenerate ground-state. We find that disorder induces a finite density of neutral solitons in the lattice dimerization of a polymer chain. Interchain interactions result in a linear potential between the solitons and, if sufficiently strong, bind them into pairs resulting in an exponential suppression of the soliton density. As neutral solitons carry spin 1/2, they contribute to the polymer's magnetic properties. We calculate the magnetic susceptibility and suggest measurements of the magnetic susceptibility in {it trans}-polyacetylene at low temperatures. Submitter: M.T.Figge@phys.rug.nl (Marc Thilo Figge