Re-Integerization of Fractional Charges in the Correlated Quarter-Filled Band

Clay, R. T., Mazumdar, S., & Campbell, D. K. (2001). Re-Integerization of Fractional Charges in the Correlated Quarter-Filled Band. Phys. Rev. Lett.. 86, 4084.

Abstract

Previous work has demonstrated the existence of soliton defect states with charges ±e/2 in the limits of zero and infinite on-site Coulomb interactions in the one-dimensional (1D) quarter-filled band. For large but finite on-site Coulomb interaction, the low temperature 2kF bond distortion that occurs within the 4kF bond-distorted phase is accompanied by charge ordering on the sites. We show that a "re-integerization" of the defect charge occurs in this bond-charge-density-wave state due to a "binding" of the fractional charges. We indicate briefly possible implications of this result for mechanisms of organic superconductivity.