Kinks of fractional charge in quasi-one-dimensional systems

Recent theoretical studies have shown that in quasi-one-dimensional conductors having a Peierls distortion of commensurability index n (ratio of the distortion period to lattice spacing), there exist excitations whose charge is Q = +- 2e/n or +- 2e/n +- e. These excitations are kinks in the order parameter describing the lattice distortion. In trans polyacetylene, n = 2 and Q = 0, +- e with spin S = 1/2, 0 respectively. For n = 3 (e.g., TTF-TCNQ at 19Kb) Q = +- 2e/3, +- e/3, +- 4e/3 with spin S = 0, 1/2, 0 respectively. Electronic states localized at the kink have energies in the Peierls gaps. Properties of these stable fractionally charged objects are discussed. (Auth.)