Fractionally Charged Excitations in Quasi-One-Dimensional Systems

Abstract

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 specing), there exist excitations whose charge is Q = ω 2e/n or ω 2e/n ± e. These excitations are kinxs in the order parameter ψ describing the lattice distortion. In trans polyacetylene, n = 2 and Q = O, ± e with spin S = 1/2, O respectively. For n = 3 (e.g. TTF-TCNQ at 19Kb) Q = ± 2/3 e, ± 1/3 e, ω 4/3 e with spin S = O, 1/2, O respectively. Electronic states localized at the kink have energies in the Peierls gaps. Properties of these stable fractionally chareged objects are discussed.