Fractionally charged excitations in the charge density wave state of a quarter-filled t-J chain with quantum phonons

Elementary excitations of the 4kF charge density wave state of a quarter-filled strongly correlated electronic one-dimensional chain are investigated in the presence of dispersionless quantum optical phonons using Density Matrix Renormalization Group techniques. Such excitations are shown to be topological solitons carrying charge e/2 and spin zero. Relevance to the 4kF charge density wave instability in (DI− DCNQI)2Ag or recently discovered in (TMTTF)2X (X = PF6, AsF6) is discussed. PACS. 75.10.-b General theory and models of magnetic ordering – 75.50.Ee antiferromagnetics – 71.27.+a Strongly correlated electron systems; heavy fermions – 75.40.Mg Numerical simulation studies