Exciton binding energy in the strong correlation limit of conjugated chains

Z. Shuai, J. Brédas, S. Pati, S. Ramasesha

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


By applying the numerically accurate symmetrized density-matrix renormalization-group method coupled with the extended Hubbard-Peierls model, we find that (i) the on-site Hubbard repulsion energy U dramatically reduces the binding energy of the lowest optically allowed (Formula presented) exciton; (ii) in the zero-dimerization limit, there exists a critical value of V at which the (Formula presented) exciton becomes bound; the critical value (Formula presented) is fully in agreement with the recent analytical results at the infinite-U limit by Gallagher and Mazumdar [Phys. Rev. B 56, 15 025 (1997)], furthermore, this critical value decreases appreciably for weaker on-site correlation strengths, when the dimerization amplitude (Formula presented) is nonzero. The present accurate numerical results contradict those obtained recently by Yu, Saxena, and Bishop [Phys. Rev. B 56, 3697 (1997)] both qualitatively and quantitatively. We also present first-order perturbation plus random-phase-approximation and single configuration-interaction analyses to rationalize the numerical calculations.

Original languageEnglish (US)
Pages (from-to)15329-15332
Number of pages4
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number23
StatePublished - 1998
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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